Kerala Agricultural University, Thrissur

The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively. Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively. On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs. In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc. During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU). Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.

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Open Access
Identification of Potential Donors for superior fruit quality traits and genes for resistance to tomato leaf curl virus (ToLCV) In tomato and allied species
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2017) Nadkarni Siddhesh, Raghvehdra; KAU; Jayalekshmy, V G
The study entitled ‘‘Identification of potential donors for superior fruit quality traits and genes for resistance to tomato leaf curl virus (ToLCV) in tomato and allied species’’ was conducted during the period 2014-2017, in the Department of Plant Breeding and Genetics, Vellayani with an objective of evaluating varieties and allied species of tomato for fruit quality traits and genes for resistance to ToLCV through biochemical analysis and molecular markers and to study compatibility for hybridization and seed set to transfer ToLCV genes to bacterial wilt resistant variety ‘’Anagha’’ from donors of related species. Thirty-four genotypes including allied species of tomato were collected from different sources and studied under four different experiments. First experiment was screening of thirty-four genotypes under natural field condition for tomato leaf curl virus resistance in summer season and scoring for ToLCV by the scale given by Banerjee and Kalloo (1987). Eight genotypes viz., EC 541109 (Solanum pimpinellifolium L.) EC 168283 (Solanum pimpinellifolium L.), IIHR1970 (Solanum peruvianum L.) and LA 2805 (Solanum lycopersicum var. cerasiforme L.), IIHR 2372, IIHR 2200, Vaibhav and Nandi were found to be highly resistant. The scions of these eight highly resistant genotypes were grafted on susceptible root stock with ToLCV symptoms. The scions did not take symptoms after 25 days confirming the resistance of the genotypes. Evaluation of thirty-four genotypes for yield and fruit quality parameters was carried out in field condition during rabi season. The analysis of variance revealed significant difference for all seventeen quantitative and fruit quality attributes. On the basis of mean performance for different yield characters, genotypes viz., Vaibhav, EC 320574, EC 165751, EC 164656 and EC 16786 were superior, whereas genotypes EC 541109, IIHR 2372, Vaibhav and LA 2805 were superior for fruit quality traits. The wild species used in the study had high content of carotene, lycopene and TSS. From coefficient of variation it was evident that the estimates of GCV were higher than the corresponding PCV for all seventeen quantitative attributes indicating the less influence of environment on the expression of these genotypes. The estimates of GCV and PCV were higher for seven characters indicating the existence of high variability in the material studied offering ample scope for selection. Heritability estimates and genetic advance as per cent of mean (GAM) were high for all characters indicating predominance of additive gene action for these characters. Phenotypic and genotypic correlation coefficient analysis with respect to weight of fruits per plant-1 showed positive significant correlation with plant height, number of primary branches plant-1, spread of the plant, number of days to 50% flowering, number of days to first fruit harvest, number of fruits plant-1, weight of fruit and volume of fruit. Path analysis confirmed that direct effect on number of fruits plant-1 expressed highest positive direct effect on weight of fruits plant-1, followed by weight of fruit, spread of the plant, lycopene content, number of primary branches plant-1, number of days to 50% flowering and number of days to first fruit harvest. Molecular markers linked to the three genes Ty2, Ty3 and Ty3a specific to ToLCV resistance were validated with thirty-four genotypes. Genotypes IIHR 2200, Vaibhav and EC168283 (Solanum pimpenellifolium L.) showed the presence of Ty2 gene and genotype IIHR 1970 (Solanum peruvianum L.) showed the presence of Ty3a gene. The identified resistant lines were crossed with ‘‘Anagha’’ the popular bacterial resistant variety with an objective to transfer the resistance. All the seven successful hybrid combinations showed 100% pollen fertility confirming the compatibility of the parents. Evaluation of seven hybrids with parents revealed significant difference for all seventeen quantitative and fruit quality attributes. On the basis of mean performance for different yield and fruit quality traits in hybrids viz., L1 x T1 (Anagha x Vaibhav) showed superiority for characters like weight of fruits plant-1, weight of fruit, volume of fruit, pH of juice and shelf life, L1 x T5 (Anagha x EC 541109) showed superiority for characters like plant height, number of primary branches, lycopene content, TSS %, and carotene content, L1 x T2 (Anagha x Nandi) showed earliness in number of days to 50% flowering and number of days to first fruit harvest, L1 x T4 (Anagha x IIHR 2372) showed superiority for traits like pericarp thickness and vitamin C. Seven hybrids were screened and scored for ToLCV, in natural field conditions. Highly resistant reaction was found in four hybrids viz., L1 x T3 (Anagha x EC 168283), L1 x T5 (Anagha x EC 541109), L1 x T6 (Anagha x IIHR 2200), L1 x T7 (Anagha x LA 2805). This study could identify resistance sources for ToLCV viz., EC 541109, EC 168283, IIHR1970, LA 2805, IIHR 2372, IIHR 2200, Vaibhav and Nandi. The genotypes Vaibhav, EC 320574, EC 165751, EC 164656, EC 16786, EC 541109, IIHR 2372 and LA 2805 which showed superiority in yield and fruit quality traits can be used for breeding for improvement of yield and quality traits. The wild species which are found compatible with cultivated species can be used as donors for quality traits as well as resistance. The hybrid L1 x T1 (Anagha x Vaibhav) with superior yield traits and resistance to ToLCV can be recommended for release after yield trials. Hybrid L1 x T5 (Anagha x EC 541109) an interspecific hybrid with superior fruit quality traits can be recommended for release as cherry tomato after trials. The segregating population of interspecific crosses can be used for further evaluation to locate plant types with good yield, fruit quality along with resistance to ToLCV.
Open Access
Development of near isogenic lines of rice variety 'uma' for blast resistance genes through molecular marker assisted backcross breeding
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2017) Harikrishnan, P J; KAU; Jayalekshmy, V G
Blast disease, caused by Magnaporthe oryzae is one of the most devastating diseases in rice and is a great threat to food security worldwide. During kharif season, the disease is prevalent throughout the rice growing areas in India including the southern states of Kerala, Tamil Nadu, Karnataka and Andhra Pradesh. Approximately 100 major blast resistance genes have been reported in rice and hence exploitation of host plant resistance through gene pyramiding can be employed effectively for the management of blast. Developing Near Isogenic Lines (NILs) ie., lines carrying each of the major resistance genes in the background of susceptible recurrent parent is a major step in the pyramiding work to be carried out for developing multi race resistant varieties. So, the present study entitled “Development of Near Isogenic Lines of rice variety „Uma‟ for blast resistance genes through molecular marker assisted backcross breeding” was undertaken at the College of Agriculture, Vellayani Thiruvananthapuram, to develop Near Isogenic lines (NILs) of rice variety Uma for blast resistance genes (Pi1, Pi2 and Pikh) using identified donors through marker assisted back cross breeding. DNA markers closely linked to the blast resistance genes viz., RM527 (Pi2 gene), RM224 (Pi1 gene) and RM206 (Pikh gene) were used for validating marker polymorphism in the identified traditional donors of blast resistance genes viz. PTB21 (Thekkan) with Pi2, PTB7 (Parambuvattan) with Pi1 and Pikh and susceptible recipient parent Uma (MO16). This validation confirmed the absence of genes in the recipient parent, „Uma‟. These polymorphic gene specific markers were used for foreground selection in F1, BC1F1 and BC2F1 plants. Hybridisation was carried out between recipient parent Uma and the two donor parents viz., PTB21 and PTB7 to transfer genes for resistance. F1 plants with heterozygous loci for blast resistance genes specific markers were identified through foreground selection and backcrossed with „Uma‟ the recurrent parent to obtain the BC1F1 generation. The BC1F1 plants were screened with foreground markers and those plants containing the respective resistance genes were identified. Among the plants screened for a particular cross, 12 were found to contain Pi2 gene, 17 had Pi1 gene and 21 plants contained Pikh gene. χ2 test was done with the genotypic data of BC1F1 plants with single genes viz. Pi1, Pi2 and Pikh. Segregation ratio in BC1F1 population from all the crosses except Uma x PTB7 (Pi1) did not show significant deviation from the expected 1:1 ratio suggesting the presence of segregation distortion in the segregants of the cross Uma x PTB7 (Pi1). For the background selection, three parental lines were genotyped with 30 microsatellite loci and the ones polymorphic for Uma and the donors were identified. Twelve markers were found to produce discrete amplicons for distinguishing Uma and PTB21 while 17 markers could distinguish Uma and PTB7. Five of the polymorphic markers were used for background selection in BC1F1 plants with resistance genes of the three crosses. The BC1F1 plants with highest percentage of recurrent parent genome recovery in the three populations were identified. Highest recovery percentage of 70 could be obtained in backcross population of all the three crosses. Morphological data for seven quantitative and one qualitative character (kernel colour) was recorded for the BC1F1 plants with the resistant genes. Euclidean coefficient of dissimilarity was assessed in comparison with the recurrent parent Uma. The Euclidean distance values ranged from 5.9 (A-21) to 21.3 (A-9) in the cross Uma x PTB21 (Pi2), 4.88 (B-8) to 17.8 (B-23) in Uma x PTB7 (Pi1) and from 4.79 (C-34) to 13 (C-15) in case of Uma x PTB7 (Pikh). All the BC1F1 plants with resistance genes were used to raise the BC2F1 generation. The BC2F1 populations of the three crosses were subjected to foreground selection and plants with resistance genes were identified. Background selection was carried out in BC2F1 plants with resistance genes using 12 polymorphic markers in the cross Uma x PTB 21 (Pi2) and 17 markers in plants identified in the BC2F1 of Uma x PTB7 (Pi1 and Pikh). Percentage of recurrent parent genome recovery ranged from 70.83 to 95.83 for the cross Uma x PTB21 (Pi2), 70.59 to 97.06 for Uma x PTB7 (Pi1) and from 61.76 to 94.12 for Uma x PTB7 (Pikh). Euclidean coefficient of dissimilarity was assessed in comparison with the recurrent parent Uma, based on seven quantitative traits (plant height, number of tillers number of productive tillers, panicle length, grain L/B ratio, thousand grain weight and days to maturity) in the BC2F1 plants with resistance genes. The lowest values of Euclidean distance were recorded in the plants A-16-6 (2.24), B-18-2 (3.35) and C-17-3 (4.33) of the three backcross populations respectively. Based on the Euclidean distance and percentage recovery of the recurrent parent genome, five plants were identified from each of the three crosses as potential Near Isogenic Lines (NILs) for the three blast resistance genes Pi2, Pi1 and Pikh. The genotype A-5-1 with a recurrent parent genome recovery of 95.83% and Euclidean distance of 5.55 with Uma was identified as the most potential NIL of Uma for the gene Pi2. Similarly B-27-1 (Euclidean distance – 4.56, % genome recovery - 97.06) and C-17-3 (Euclidean distance - 4.33, % genome recovery - 94.12) were identified as potential NILs for Pi1 and Pikh genes respectively. Selfed seeds (BC2F2) were collected from the identified potential NILs. The present research could identify NILs of Uma for three blast resistance genes viz., Pi1, Pi2 and Pikh with more than 94% recurrent parent genome recovery with two backcrossing through marker assisted selection. This confirms the utility of marker assisted backcross breeding in recurrent parent genome recovery. The NILs can be used in intermating programmes in future to develop pyramided lines of Uma with all the three blast resistance genes (Pi1, Pi2 and Pikh) to ensure high yielding ability and durable broad spectrum resistance to the blast pathogen.
Open Access
Genetic diversity and combining ability in cucumber (Cucumis sativus L.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2017) Suma, A; KAU; Elsy, C R
Assessment of genetic diversity is the key tool in any crop improvement and germplasm management programme. Evaluation of genetic variation will help to provide valuable information about new sources of genes. The studies on combining ability and heterosis can support utilization of promising lines in further crop improvement programmes. Cucumber (Cucumis sativus L. 2n= 2x= 14) is an indigenous vegetable crop of India. Even though rich diversity for cucumber is available in India, studies on genetic diversity of this crop are scanty. Therefore, the present project was proposed to explore genetic diversity in cucumber using morphological and molecular markers and to study combining ability and heterosis in selected genotypes. Morphological characterization of 50 accessions of cucumber revealed presence of significant difference among accessions for majority of vegetative, floral and fruit characters. Mean days to first male and female flower opening was 36 and 43 days respectively. Majority of the accessions possessed elliptical elongated fruits with light green skin colour and white flesh colour. Sixteen accessions exhibited significantly higher fruit length than AAUC-2, the standard check, the maximum being exhibited by IC613472 (20.85 cm). Accessions with oblong ellipsoid fruits possessed higher fruit diameter. Mean fruit weight showed high variability among accessions with a range of 33 g to 343 g. Fourteen accessions exhibited significantly high yield than AAUC-2. Number of fruits per plant, yield per plant, loss of weight during storage and sex ratio showed high values for all the genetic parameters studied. IC613481 was the promising genotype identified in morphological characterization, followed by IC613480. Cluster analysis grouped accessions into seven distinct clusters based on the level of similarity in quantitative characters. Random grouping of accessions into various clusters indicated absence of parallelism between genetic diversity and geographical diversity. Cluster II and III were the largest clusters, with 14 accessions each and Cluster V and VI, the smallest ones with single accession each. Results of Principal component analysis revealed that first three principal components, with Eigen values more than unity accounted for 85.80 per cent of cumulative variance, contributed by fruit weight, fruit length, fruit diameter and days to first harvest. The diversity analysis of the accessions was done using DIVA-GIS by generating grid maps. The results of the study indicated that highly diverse accessions with respect to the selected characters were sourced from Mizoram, Tripura and West Bengal. Molecular characterization revealed high level of genetic distinctness between genotypes. SSR11742 and AF202378 were found to be highly polymorphic markers, with high polymorphism information content and number of polymorphic bands. In-depth evaluation of selected 22 genotypes revealed significant difference for all fruit characters except days to last harvest and harvest duration and further revealed the superiority of IC613480. Evaluation of 15 hybrid combinations developed through half diallel mating design and their parents indicated presence of significant difference among parents and hybrids for various characters studied. Among the parental genotypes, IC613480, exhibited significantly high GCA effects for fruit length, number of fruits per plant and yield per plant whereas IC595508A, for fruit weight and loss of weight during storage, and IC613485 for fruit diameter, thus proving to be promising parents for accumulating genes for these characters. The hybrids, IC613480 x IC595508A and IC613480 x IC613471 showed significant SCA effects for yield per plant and sex ratio. IC613480 x IC613471, IC613480 x IC595508A and IC613471 x IC595508A were exhibiting significantly high relative heterosis, heterobeltiosis and standard heterosis for number of fruits per plant and yield per plant. IC613480 and IC613485 were the most promising genotypes identified from the study whereas IC613480 x IC613471 was the most promising hybrid based on SCA effects, heterosis, per se performance on yield contributing characters and organoleptic qualities. This hybrid showed high fruit length (17.01 cm), yield per plant (2163.45 g), number of fruits per plant (11.43) and sex ratio (0.11). IC613480 x IC613476 and IC613485 x IC595508A were the other promising hybrids.
Open Access
Genetic analysis of drought tolerance in rice (Oryza sativa L.)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2017) Patil Krantikumar, Haunsajirao; Lekha Rani, C
The research work entitled “Genetic analysis of drought tolerance in rice (Oryza sativa L. )” was carried out in the Department of Plant Breeding and Genetics College of Agriculture,Vellayani, Thiruvananthapuram during the period 2014 – 2016. The study aimed at estimating the nature and magnitude of gene effects in the inheritance of drought tolerance in rice under upland conditions. Screening of the selected parents and superior progenies for the presence of molecular markers associated with drought tolerance was envisaged. Twenty diverse genotypes including varieties recommended for uplands and popular high yielding varieties widely cultivated in the state were screened for drought tolerance under rainfed upland condition during May to October, 2014. Morphological observations were taken at appropriate plant growth stages following the Standard Evaluation System for Rice [IRRI, 1996]. The screening of genotypes was done as per the protocols of DRR (2012). The rice genotypes were further screened for drought tolerance imposing reproductive stage moisture stress under protected condition. The data from rainfed and protected condition screening were utilized for the development of a selection index based on which the genotypes were ranked. The six top ranking genotypes with high yield and drought tolerance viz., Vaishak, Thottacheera, Kalladiaryan, Vyttila 6, Harsha and Swarnaprabha were hybridized in half diallel pattern. The 15 F1 hybrids were evaluated along with their parents under rainfed situation to select the top five heterotic hybrids which were carried forward to F2. In all populations studied, qualitative traits related to drought such as nature of panicle exsertion (DRR, 2004) and scoring for leaf rolling (IRRI, 1991) were analysed. Degree of panicle exsertion has a direct bearing on spikelet sterility. Leaf rolling is a tricky character where the breeder has to strike a balance between the onset, intensity and duration of rolling as well as the recovery from rolling when moisture is provided. This is because leaf rolling reduces transpiration loss at the expense of photosynthate production. Mild incidence of insect pests viz., gandhi bug and leaf folder and diseases viz., brown spot, blast and bacterial leaf blight was observed in the field experiments. The variety Swarnaprabha had good cooking quality. Kanchana had excellent milling recovery and good cooking quality with high volume expansion on cooking and comparatively high protein content. Prathyasha had high nutrient content and good cooking quality. Aathira possessed excellent milling recovery and cooking quality. Parambuvattan had appreciable quality and is preferred for certain special preparations. The traditional upland varieties viz., Katta Modan, Karutha Modan and Chuvana Modan had superior milling recovery. High PCV and GCV values were observed for yield related characters such as filled grains panicle-1, grain yield plant-1, harvest index etc. Based on the studies on correlation and path coefficient analysis, biological yield plant-1, harvest index and panicle length exhibited maximum positive direct effect on grain yield. Vaishak was the best combiner for panicle length, number of spikelets panicle-1, spikelet fertility, total chlorophyll content, leaf temperature and good combiner for number of filled grains panicle-1, proline content, cell membrane stability index, chlorophyll a, chlorophyll b, total chlorophyll content, leaf temperature, transpiration rate, leaf soluble protein content and number of days for reaching critical stress level. Thottacheera was a good general combiner for days to 50 % flowering, total chlorophyll content and leaf temperature. Kalladiaryan showed good general combining ability for number of productive tillers plant-1, straw yield plant-1, proline content, chlorophyll b content and total chlorophyll content. Vyttila 6 was the best combiner for plant height at maturity and also for physiological and biochemical traits such as water use efficiency, relative leaf water content, proline content, cell membrane stability index, chlorophyll a content, carotenoides content, leaf temperature, transpiration rate, stomatal conductance, leaf soluble protein content and good combiner for total chlorophyll content and number of days taken for reaching critical stress level. Harsha was a good general combiner for short stature at maturity, 1000 grain weight and grain weight panicle-1 while parent Swarnaprabha showed good general combining ability for number of days taken for reaching critical stress level. Considering the preponderance of non additive gene action for most of the characters and gca and sca variances it can be concluded that heterosis breeding would yield better results. The hybrids Vyttila 6 x Harsha, Vyttila 6 x Swarnaprabha and Vaishak x Thottacheera exhibited highest heterosis for grain yield under upland condition. Six parents and their best hybrids were subjected to molecular analysis using three SSR markers linked to quantitative traits. The allele linked to the respective trait was present in all the hybrids, as in the parent with resistance to drought. Transgressive segregants for yield and yield attributing traits were observed in the F2. The F2 segregants Vaishak x Swarnaprabha, Vaishak x Thottacheera and Vaishak x Kalladiaryan were early maturing, playing an important role in the mechanism for drought escape. Drought tolerance mechanism can also be attributed to these segregants. These types will be valuable for the development of early maturing drought tolerant upland varieties. . The hybrids Vyttila 6 x Harsha and Vyttila 6 x Swarnaprabha ranked best for grain yield plant-1. Drought resistance was conferred to these hybrids via. , root length and osmotic adjustment traits and the hybrids had various yield attributing traits also , which was further confirmed by trait specific SSR markers. Desirable F2 segregants from the combinations Vaishak x Swarnaprabha, Vaishak x Thottacheera and Vaishak x Kalladiaryan may be carried forward further for the development of drought escaping early maturing upland varieties with high grain yield. The combinations Vyttila 6 x Harsha and Vyttila 6 x Swarnaprabha can be carried forward further for the development of drought tolerant upland varieties with high grain yield.
Open Access
Pyramiding bacterial leaf blight resistance genes into popular rice varieties of Kerala through marker assisted selection
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2017) Ramaling Hundekar; Jayalekshmy, V G
Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a devastating disease of rice in Asia and Africa . Major rice growing areas of Kerala are highly prone to this disease which results in damage upto 35%. Exploitation of host plant resistance is the only practical strategy for managing the disease in an ecofriendly manner. Till date, more than 40 resistance genes for BB have been identified from diverse sources and pyramiding of these resistance genes will impart durable resistance. So, present study entitled “Pyramiding Bacterial Leaf Blight resistance genes into popular rice varieties of Kerala through marker assisted selection” was undertaken at the College of Agriculture Vellayani Thiruvananthapuram, to pyramid the genes for resistance to bacterial blight (xa13, Xa21, Xa33, Xa38) into the popular rice varieties, Prathyasa and Aiswarya through foreground selection for the genes using molecular markers, to obtain lines with the two/three resistance genes combination in the background of above cultivars. DNA markers closely linked to the BB resistance genes, such as pTA248 (Xa21 gene), xa13 pro (xa13 gene), RMWR7.1 (Xa33 gene) and Oso4g53050- 1(Xa38 gene) were used for validation of the marker polymorphism in the donors of the genes for resistance to BB viz. Improved Samba Mahsuri with xa13 and Xa21, Improved Samba Mahsuri with Xa33, and PR-114 with Xa38 and susceptible recipient parents Aiswarya and Prathyasa . This validation confirmed the absence of the genes in the recurrent parents chosen for the study. These polymorphic markers were also used for foreground selection in F1 plants and backcross generations. Initial hybridization was performed between two recipient parents and three donor parents to transfer the genes for resistance. Foreground selection was carried out in 193 F1 plants from these six crosses using molecular markers specific to the genes. F1 plants (163) with heterozygous loci for trait specific marker were backcrossed with respective recurrent parent and obtained 776 BC 1F1 plants in six cross combinations. These plants were screened with four trait specific foreground markers and 279 plants were identified with genes of interest. From among these forty two plants in the 2 crosses Aiswarya x ISM (xa13 and Xa21) and Prathyasa x ISM (xa13 and Xa21) had both genes (xa13 and Xa21) in heterozygous condition. χ2 test was done with the genotypic data of BC1F1 plants with single gene viz. Xa33 and Xa38. Segregation ratios in BC1F1 population from the crosses viz. Prathyasa x ISM (Xa33), Aiswarya x PR-114(Xa38) and Prathyasa x PR-114(Xa38) did not show significant deviation from the expected 1:1 ratio. But BC1F1 plants with Xa33 gene of the cross Aiswarya x ISM showed significant deviation from 1:1 segregation ratio. This suggests the presence of segregation distortion in these segregants. For the background selection four varieties were genotyped with 270 microsatellite loci and 180 discrete, unambiguous amplicons specific for the four varieties were identified. The background selection was carried out on altogether 279 plants from six BC1F1 populations using 143 loci polymorphic in the parents. The BC1F1 plants with highest percentage of recurrent parent genome recovery in the six populations were selected based on the background markers. These plants were used for intermating programme to pyramid the genes. The disease screening of donors, Improved Samba Mahsuri(xa13 and Xa21), Improved Samba Mahsuri (Xa33), and PR-114 (Xa38) against local isolate of Xanthomonas oryzae pv.oryzae conducted at RRS, Moncompu showed resistant disease reaction in the donors ISM (xa13 and Xa21) and ISM (Xa33). PR- 114(Xa38) exhibited moderate susceptible disease reaction and so this donor was excluded from further breeding programme. BC1F1 plants having xa13 and Xa21 genes were used as female parent and BC1F1 plants with Xa33 used as male parent in intermating programme for pyramiding. Foreground selection was performed in the intermated plants using trait specific markers. Among Aiswarya derived BC1F1 intermated plants, seven plants showed three resistance gene combination (Xa21+ xa13 +Xa33) and forty four plants showed two resistance gene combinations. Among the forty four plants with two resistance gene combination, seventeen had xa13+Xa33, 18 had Xa21 + xa13 and 9 had Xa21 + Xa33. In Prathyasa derived BC1F1 intermated plants 12 plants had Xa21+xa13 gene combinations and nine had xa13 + Xa33 resistance gene combination. Based on the four quantitative traits (plant height, number of productive tillers, grain L/B ratio and days to maturity) Euclidean coefficient of dissimilarity was assessed in comparison with the respective recurrent parents, in plants pyramided with resistance genes. In Aiswarya derived pyramided plants coefficient of dissimilarity with Aiswarya for the four quantitative traits varied from 2.24 to 27.25. Coefficient of dissimilarity with Prathyasa in the Prathyasa derived pyramided lines based on the four quantitative traits ranged from 3.00 to 17.47. The morphological traits of the two / three gene pyramided BC 1F1 genotypes were found to be either superior or on par with the recurrent parents Aiswarya and Prathyasa. Majority of pyramided lines showed red kernel colour of the recurrent parents. This research lead to development of plants pyramided with two /three genes for resistance to BB in the background of Aiswarya and plants with two resistance genes in the background of Prathyasa. These pyramided lines can be used for further breeding programme to develop Essentially Derived Varieties (EDVs) to tackle the Bacterial Leaf Blight (BB) disease.
Open Access
Genotyping of Rf (restoring fertility) loci of rice varieties of Kerala using molecular markers
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2017) Rajib, Das; KAU; Jayalekshmy, V G
Hybrid rice technology aims to increase the yield potential of rice beyond the level of high yielding varieties by exploiting the phenomenon of hybrid vigour or heterosis. It is the only technology available now to break the yield plateau attained in rice. Commercial production of hybrid rice can be achieved through three line system of hybrid rice development. Identification of restorers and maintainers for the system is the initial step in hybrid rice breeding. So the present study entitled “Genotyping of Rf (Restoring fertility) loci of rice varieties of Kerala using molecular markers” was undertaken as an initial step for the development of hybrid rice for Kerala with the objectives to locate restorers and maintainers from Kerala rice varieties using molecular markers, validation of the restoration of fertility in cross with WA Cytoplasmic Male Sterile (CMS) lines, study of inheritance pattern of restorer gene and to locate heterotic combiners from the possible restorers and maintainers. In the present study twenty one rice varieties were screened with 13 SSR markers linked to different Rf genes i.e Rf3, Rf4, Rf5, Rf6 and Rf7. Three varieties had only one Rf gene, seven varieties had two Rf gene, four varieties had three Rf gene. Rice varieties Remya, Manupriya and Swarnaprabha had four Rf genes and PTB-9 had all the Rf genes. For identification of maintainers and restorers from among the 21 rice varieties under study, these lines were crossed with 4 CMS lines (IR58025A, UPRI95-17A, CRMS31A and CRMS32A). Pollen and spikelet fertility of the hybrids recorded that Remya, Swarnaprabha, Manupriya, Varsha and Aiswarya were restorers for CMS line IR58025A, Remya, Jayathi, Annapoorna, Neeraja, Aiswarya and Pavizham were restorers for UPRI95-17A. Remya, Jayathi, Swarnaprabha, Kanakom and Neearaja were restorers for CRMS31A and Remya, Jayathi, Swarnaprabha, Annapoorna, Kanakom, Mattatriveni and Pavizham were restorers for CRMS32A. Rice variety Remya alone was found to be the restorer for all four CMS lines. Rice varieties Jyothi, Kanchana and Aruna were identified as maintainers for IR58025A. Only one variety Kanchana identified as maintainer for UPRI95-17A. Bharathy, Jyothi, Kanchana and Aruna were identified as maintainers for CMS line CRMS31A, while Kanchana and Bharathy were identified as maintainers for CRMS32A. Kanchana alone was found to be the maintainer for all four CMS lines. In field validation Remya which had 4 Rf genes (Rf3, Rf4, Rf5 and Rf6) was found to be a restorer for all the lines with WA Cytoplasm studied. All the restorers identified through field validation had either Rf3 or Rf4 gene which were reported as the major genes for fertility restoration. Study of inheritance pattern of restorer gene was analysed in F2 generation of the crosses between CMS lines and the restorers. It was found that in UPRI95-17A x Remya, UPRI95-17A x Jayathi, UPRI95-17A x Annapoorna, UPRI95-17A x Aiswarya and UPRI95-17A x Pavizham the restoration of fertility is governed by 2 dominant gene. Co-segregation of the molecular marker linked to Rf loci and the trait of restoration of fertility in the segregating population was analysed through Bulk Segregant Analysis (BSA) and found co-segregation of marker RM1 with Rf3 gene and marker RM171 with Rf4 gene. This shows that the marker loci and fertility restoration genesRf3 and Rf4 are tightly linked. To assess the genetic parameters of the selected twenty one rice varieties they were grown in completely randomized block design with 2 replications in pots and observations were taken on 12 metric traits. The study revealed high heritability coupled with high genetic advance as per cent of mean for Pollen fertility, number of spikelets/panicle, number of filled grains/panicle, LB ratio, number of grains/panicle and grain yield/plant. Hence these traits are predominantly under the control of additive gene action and hence these characters can be improved by selection. Grain yield per plant recorded a significant positive correlation with total no of tillers, number of productive tillers per plant, panicle length, number spikelets/panicle, number of filled grains/panicle, number of filled grains per panicle. Divergence analysis grouped the rice varieties into eight clusters. Cluster II consisting of Mattatriveni and cluster VI consisting of Jayathi, Swarnaprabha, Kanakom and Aiswarya was the farthest. The hybrid developed from 23 crosses between identified restorers and 4 CMS lines were evaluated for heterosis and identified promising hybrids were UPRI95-17A x Aiswarya, UPRI95-17A x Neeraja, UPRI95-17A x Remya and CRMS31A x Kanakom based on high mean grain yield per plant and high standard heterosis over standard check Uma. In order to assess heterosis in different combination of the identified maintainers and restorers an L x T analysis was done with maintainers as the lines and restorers as the testers. Perusal of findings indicated that line Jyothi is a good general combiner as it recorded a high over all GCA status. The hybrid Aruna x Varsha was the best specific combiner followed by, Jyothi x Pavizham and Kanchana x Mattatriveni. Three crosses viz; Aruna x Varsha, Jyothi x Pavizham and Bharathy x Annapoorna registered high significant heterosis for grain yield per plant over mid parent, better parent and standard check Uma. The present study could identify restorers and maintainers for 4 CMS lines from the Kerala rice varieties and also heterotic combination of restorers and maintainers. By reconstituting the identified maintainer with sterile cytoplasm of the CMS lines heterotic hybrids with grain qualities specific to Kerala can be developed. The superior hybrids obtained from identified restorers and CMS lines can be directly used for commercial release after yield trial.
Open Access
Inheritance of yield and resistance to shoot and fruit borer (Leucinodes orbonalis GUEN.) in brinjal (Solanum melongena L.)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2017) Gangadhara, K; KAU; Mareen Abraham
The present study entitled "Inheritance of yield and resistance to shoot and fruit borer {Leucinodes orbonalis Guen.) in brinjal {Solanum melongena L.)" was conducted at College of Agriculture, Vellayani during 2012-15 with the major objective to study the genetic basis of yield, yield attributes and developing high yielding shoot and fruit borer resistant varieties of brinjal. Molecular comparison of resistant and susceptible segregants will also be done In the first experiment, 60 genotypes were evaluated using RED with two replications. Evaluation was carried out in both kharif and rabi seasons for yield as well as for shoot and fruit borer resistance in two parallel experiments. Analysis of variance revealed significant difference among the accessions for all the characters under study. High PCV and GCV were recorded for plant height, number of primary branches planf^ intra cluster distance, number of fruits plant"', length of fhiits, girth of fruits, fruit weight, fiiait yield plant"' and shoot and fruit infestation. High heritability coupled with high genetic advance as per cent mean was observed for plant height, number of primary branches plant"', intra cluster distance, inter cluster distance, number of fruits plant*', length of fruits, girth of fruits, fruit weight, fhiit yield plant"' and shoot and fhiit infestation in both seasons. Fruit yield plant"' showed significant positive correlation with fhiits plant"', fruit weight, fruit girth, plant height, number of primary branches plant"', fruit length and percent of long styled flowers in both the seasons at phenotypic and genotypic level. Path coefficient analysis revealed that fruits plant"' showed high positive direct effect on yield followed by fruit weight, per cent long styled flowers, per cent medium styled flowers and days to first harvest in both the seasons. SM 36 followed by SM 2, SM 9, SM 14 and SM 21 was having the highest selection index values based on discriminant function analysis in both the seasons. Screening of 60 accessions based on the per cent of infested shoots and fruits were recorded at 10 days interval from 30 H2 to 100 DAT. The minimum per cent of shoots and fruits infestations was recorded in SMI followed by SM 60 and SM 59 in both kharif and rabi season. The second experiment was laid out in RBD with three replications with five high yielding susceptible genotypes namely SM 36, SM 2, SM 9, SM 14 and SM 21 along with three resistant genotypes viz., SM 1, SM 60 and SM 59. These were crossed to produce fifteen hybrids in a line x tester pattern with Haritha as check. Heterosis and combining ability were estimated for plant height, primary branches plant"', days to first flowering, per cent long styled flowers, per cent medium styled flowers, per cent short styled flowers, fruit length, tuit girth, fhiit weight, fhiits plant*', days to first harvest, days to last harvest and ftuit yield plant"'. Analysis of variance revealed significant differences among the genotypes for all the traits studied. The maximum standard heterosis for yield per plant was observed in the cross Raidurg Local X Pusa Purple Cluster followed by lC-433678 X IC-89986, Jagaluru Local X Vellayani Local, IC-345271 X Pusa Purple Cluster and Tiptur Local X Pusa Purple Cluster. The hybrid IC-433678 X IC-89986 and Raidurg Local X Pusa Purple Cluster showed high significant standard heterosis for number of fruits plant*', long styled flowers, fhiit weight, days to first harvest and days to last harvest. The gca values revealed that two lines (IC- 433678 and Raidurg local) and one tester (Pusa Purple Cluster) as good general combiners for fhiit yield plant"'. These lines and testers were also best combiner for yield component characters like number primary branches plant"', days to first flowering, per cent medium styled flower, per cent long styled flowers, number of fhiits plant"' and length of fruit. The estimates of specific combining ability effects indicated that IC-433678 X IC-89986, Tiptur Local X Vellayani Local, Raidurg Local X Pusa Purple Cluster, Jagaluru Local X Vellayani Local and IC-345271 X Pusa Purple Cluster were most promising for fmit yield plant* '. Out of fifteen hybrids screened for shoot and fhiit borer resistance at lOdays interval 3 G'i L from 30 to 100 DA, the hybrids IC-433678 X IC-89986 and Raidurg Local X Pusa Purple Cluster were found highly resistant. In the third experiment, high yielding hybrids IC-433678 X IC-89986 and Raidurg Local X Pusa Purple Cluster with shoot and fruit borer resistance were further advanced to F2 generation to carry out the bulk segregant analysis. The pools contrasting for shoot and fhiit borer resistance were analyzed with 22 RAPD primers along with their respective parents and three primers namely OPC-4, OPL-9 and OPO- 20 has shown polymorphic band between the bulks. In the present study two superior crosses IC-433678 X IC-89986 and Raidurg Local X Pusa Purple Cluster were identified which could be further carried forward carry forward to develop a resistant varieties to shoot and fruit borer. The three primers namely OPC-4, OPL-9 and OPO- 20 can be used to develop a scar marker which could be used further resistance breeding.
Open Access
Characterisation and genetic improvement in rose (Rosa spp.) through mutagenesis
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2017) Brunda, S M; KAU; Lekha Rani, C
The present investigation entitled “Characterisation and genetic improvement in Rose(Rosa spp.) through mutagenesis” was carried out in College of Agriculture Vellayani and RARS,Ambalavayal during the period 2014-2017.The major objective of the study was to assess the natural variability available in Hybrid Tea and Floribunda groups of roses and to analyze the effectiveness of gamma rays and Ethyl methane sulphonate(EMS) on inducing variability in them for improved plant architecture and floral characters. The first part of the programme consisted of evaluation and characterization of germplasm of Hybrid Tea and Floribunda groups of roses. For assessing genetic variability and diversity, twenty five varieties under each group were studied with respect to thirteen morphological characters. ANOVA revealed highly significant differences among the genotypes for all the traits analysed. In Hybrid Tea accessions, moderate values of PCV and GCV were obtained for number of leaves at first flower, number of petals per flower, size of petals and number of flowers per plant. In Floribundaaccessions, high estimates of PCV and GCV were obtained for number of days to first flower and prickle density. High heritability coupled with high genetic advance as percent of mean was observed for number of days to first flower, number of leaves at first flower and number of petals per flower in accessions belonging to Hybrid Tea group whereas in Floribunda group, flower size, number of days to first flower, number of leaves at first flower and number of petals per flower exhibited high heritability and genetic advance. The twenty five rose genotypes each under Hybrid Tea and Floribunda were grouped into ten and nine clusters respectively on the basis of Mahalanobis D2 statistic. The higher number of clusters obtained under each group is an indication of the genetic diversity within the group. In both the groups of roses, it was observed that the characters number of days to first flower and number of leaves at first flower contributed maximum towards genetic divergence. Cluster means of economically important characters were determined. The second part of the programme included induced mutagenesis using physical and chemical mutagens. The physical mutagen used was gamma rays.For fixing LD50 value,budwoods of four varieties viz., Pink Panther and Demestra(both under Hybrid Tea) andGolden Fairy and Monnalisa, (both under Floribunda)were treated with nine doses of gamma rays ranging from 20 to100 Gy along with control. The doses were fixed specifically based on LD50 values and were administered to the four different varieties. M1was field planted and was evaluated for thirteen morphological characters. Statistical analysis of quantitative characters showed that for an increase in gamma ray doses, a proportionate significant decrease for various plant growth parameters was evident. Mutants in plant architecture, leaf characters and floral characters were also recorded. Chemical mutagen treatment was done using EMS on in vitro cultures of four varieties viz., SchlossElutin, Jogan, Josepha and Morning Sun. Regeneration protocols for nodal explants were first standardized. The best in vitro culture medium for culture establishment comprised of MS+BA(2.0 mg/l)+ADS(25 mg/l).The best medium for shoot proliferation was BA(2.0 mg/l)+IAA(0.25 mg/l)+ADS(25mg/l) and the best medium for root induction was identified as 1⁄2 M.S+IBA(0.2 mg/l)+sucrose(2%)+BA(2.0mg/l). In vitro cultures of genotypes viz., SchlossElutin, Jogan, Josepha and Morning Sun were treated with twelve doses of EMS ranging from 0.1to1.2% along with control for three durations (30,60 and 90 minutes) for fixing LD50 value.Maximum survival was recorded in 30 minutes treatment and hence it was selected. The doses were fixed specifically for the four varieties based on LD50values. Five doses including control were administered to the different varieties and field planting of M1 was done. EMS treated invitroderived M1 was evaluated for thirteenmorphological characters. Most of the vegetative and floral parameters showed a decrease in mean valueswith increase in doses of mutagen. Induced mutagenesis, both physical and chemical, resulted invariations in form and colour of flowers and leaves in M1.Variations in form of flowers was recorded in Pink Panther, Demestraand Monnalisa. Out of these, the variation in form isolated in Pink Panther at 20 Gyis a novelty. The mutant had very shapely semi-open flowers in contrast to the fully open flowers of the parent.Demestraat 30 Gyshowed form and colour variation.In one of the variants, the flower was found to be star shaped with paleorange colour in contrast to the pale yellow with dark golden yellow centre in the parent. Among the mutants derived, two leaf variants were also isolated from Demestra and Monnalisa through gamma rays.In EMS treatment, SchlossElutin and Josepha yielded desirable colour mutants.No seed setting was observed in M1. RAPD analysis of the selected parental rose varieties and mutants was done. Based on the presence or absence of polymorphic bands, variation was detected at the molecular level. Ten RAPD decamer primers were used to check parental polymorphism. Among them,twoprimers viz.,OPA-4 and OPD-8that were highly polymorphic.Polymorphism between the parent cultivar Monnalisa and its mutants could be demonstrated using two polymorphic primers viz., OPD-8 and OPA-4. In conclusion, the extent of variability in Hybrid Tea and Floribunda groups of roses was found to be high as is evident from clustering based on Mahalanobis D 2 statistic. Both gamma rays and EMS could induce variations in form and colour of flowers andcolour of leaves.Among the mutants derived three flower colour variants viz., in Demestra at 30 Gy, SchlossElutin at 0.5% and Josepha at 0.8% and one flower form variant in Pink Panther at 20 Gy were found to be promising and were carried forwarded to the M1V1generation by budding. The M1 mutants isolated can be carried forwarded by in vitro means by taking explant from the plant part showing variation to see if solid mutants can be developed. These may be released directly as varieties or utilised in further breeding programme.

Kerala Agricultural University, Thrissur

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