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Open Access
Gene pyramiding for bacterial blight resistance in rice variety Uma (Mo 16)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2016) Tintumol, Joseph; KAU; Rose Mary, Francies
Exploiting host-plant resistance through pyramiding of resistance genes have been recommended as the best approach to impart durable resistance to rice varieties in order to combat the bacterial blight (BB) disease caused by Xanthomonas oryzae pv.oryzae (Xoo). In lieu of this, F1s were produced by hybridizing the susceptible elite rice variety Uma with resistant donor parent Improved Samba Mahsuri (ISM) harbouring three R-genes xa5, xa13 and Xa21. BC1F1 individuals were generated by backcrossing the F1s using variety Uma as the recurrent parent. The present study aimed to identify the R-genes introgressed individuals in the BC1F1 population as well as to produce BC2F1s and BC1F2s of the identified R-genes introgressed BC1F1s. Foreground selection of the BC1F1 individuals was done using the R gene linked molecular markers. Restriction digestion of the PCR product of STS marker RG 556, linked to R gene xa5, with Dra1 restriction enzyme, resulted in production of alleles of size 128 bp, 514 bp, 587 bp, 624 bp, 650 bp and 836 bp in all the BC1F1 individuals as well as the parents indicating the presence of R gene xa5 in all the individuals studied. Amplification of DNA of the individuals with the functional marker xa5 SR further confirmed the presence of R gene xa5 in both the parents as well as in all the BC1F1s. Restriction digestion of the PCR product of STS marker RG 136, linked to R gene xa13, with Hinf1, produced alleles similar to that of the donor parent ISM in three BC1F1s namely, plant no. 8.3.2, plant no. 8.3.3 and plant no. 8.3.9, indicating the presence of R gene xa13 in these plants. The presence of gene xa13 in the identified BC1F1s was further affirmed by using the functional marker xa13 promoter. The analysis had resulted in the production of 560bp allele associated with the resistant allele of gene xa13 in homozygous state from donor parent ISM in the three BC1F1s mentioned above. Out of the 95 BC1F1 individuals scored with the STS marker pTA 248 linked to R gene Xa21, only BC1F1s plant no. 8.3.2, plant no. 8.3.3 and plant no. 8.3.9 were found to possess Xa 21. Results thus obtained revealed thatBC1F1plant no. 8.3.2, plant no. 8.3.3 and plant no. 8.3.9 were R gene pyramids (xa 5+xa 13+ Xa 21). Background profiling of the three R-genes introgressed BC1F1s using 22 rice microsatellite markers, revealed presence of the donor parent allele in the homozygous state. PCR analysis with the marker RM 307, however, revealed the presence of alleles from both the parents, ISM and Uma in the BC1F1 plant no. 8.3.2. This indicated that the plant was heterozygous at the marker locus and can be expected to segregate for the alleles at this locus in subsequent generations. Considering the segregation of the 22 markers the per cent recurrent parent genome recovery in the R-genes introgressed BC1F1s was estimated to be higher in BC1F1 plant no.8.3.2 but lower than the expected estimate of 75 per cent. This was also confirmed by graphical genotyping. The dendrogram thus generated out of the marker data, grouped the R-genes introgressed BC1F1s with ISM indicating that the three R-genes introgressed BC1F1s exhibited greater similarity with donor parent parent ISM at the genome level. Evaluation of BC1F1 individuals for morphological traits revealed presence of wide variability. The three R-genes introgressed BC1F1s were late in flowering compared to the recurrent parent Uma. Two of these genotypes i.e.,plant no. 8.3.2 (234 days) and plant no. 8.3.3 (228 days) flowered later than the donor parent. However, the three R-genes introgressed BC1F1s resembled the recurrent parent Uma with respect to grain and kernel characteristics. Backcrossing the three R-genes introgressed BC1F1s i.e., plant no. 8.3.2, plant no. 8.3.3 and plant no. 8.3.9 to the recurrent parent Uma resulted in 28 BC2F1s. Simultaneously, selfing of these individuals produced 850 BC1F2 seeds. Foreground and background profiling of these generations can ensure precise identification of genotypes that resembles the recurrent parent Uma possessing the resistance genes of interest with maximum recovery of recurrent parent genome.
Open Access
Evaluation of superior cultures for yield and yellow vein Mosaic resistance in okra
(Department of Plant Breeding and Genetics College of Agriculture, Vellayani, 2016) Nikitha, J; KAU; Arya, K
The present study entitled “Evaluation of superior cultures for yield and yellow vein mosaic resistance in okra (Abelmoschus esculentus (L.) Moench)” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2014-2016, with the objective to identify high yielding and yellow vein mosaic resistant cultures of okra from those evolved through inter-varietal hybridization programme. Fifteen superior cultures of okra obtained from the previous project in the Department viz., VLYA 1, VLYA 2, VLYA 3, VLYA 4, VLYA 5, VLYA 6, VLYA 7, VLYA 8, VLYA 9, VLYA 10, VLYA 11, VLYA 12, VLYA 13, VLYA 14 and VLYA 15 along with two check varieties Varsha Uphar and Kiran were evaluated in a Randomized Block Design (RBD) with three replications during summer season of 2015. The analysis of variance was calculated for the traits under study viz., days to 50 per cent flowering, number of fruits plant-1, fruit weight (g), fruit length (cm), fruit girth (g), yield plant-1 (g), plant height (cm) and duration (days) and these were found to be highly significant for all the genotypes evaluated. The maximum yield was recorded by the genotype VLYA 2 which was on par with genotypes VLYA 5, VLYA 10, VLYA 11, VLYA 13 and VLYA 15 and the minimum yield was observed by the check variety Kiran. The yield plant-1 exhibited moderate GCV (18.42%) and PCV (19.05%), high heritability (94.00%) coupled with high genetic advance (36.69%). The yield plant-1 was found to be significantly and positively correlated with number of fruits plant-1, fruit length, fruit girth, fruit weight and plant height both at genotypic and phenotypic levels. Days to 50 per cent flowering and yellow vein mosaic disease incidence was found to be negatively correlated with yield plant-1. Very high positive and significant inter-correlation was noticed between height of plant and number of fruits plant-1. The path analysis showed that number of fruits plant-1 and fruit weight showed the maximum positive direct effect towards yield. The number of fruits plant-1 had high indirect effect through fruit length. The scoring for yellow vein mosaic disease and the vulnerability index revealed that the genotypes VLYA 5, VLYA 11 and VLYA 13 were resistant to the disease during all stages of crop growth. Number of white flies was found to be highest in VLYA 10 and lowest in VLYA 2. The incidence of fruit and shoot borer was also scored and five genotypes viz., VLYA 2, VLYA 4, VLYA 11, VLYA 13 and VLYA 14 were found to be immune and VLYA 3, VLYA 5, VLYA 15 and Varsha Uphar were found to be resistant. The glass house experiment of vector transmission and graft transmission was conducted for the confirmation of disease resistance and the vulnerability index was calculated to check the severity of the disease. The genotypes VLYA 5, VLYA 11 and VLYA 13 received a score ‘0’ which indicated that these genotypes were highly resistant. Hence the genotypes which obtained a vulnerability index of ‘0’ during both field evaluation and glass house experiment were confirmed to be resistant to yellow vein mosaic disease. Hence the present study revealed that the cultures VLYA 5, VLYA 11 and VLYA 13 were having high yield and yellow vein mosaic disease resistance. So these genotypes can be used for further trials before releasing for field cultivation.
Open Access
In vitro mutagenesis and evaluation of somatic embryo derived plantlets in cassava (Manihot esculenta Crantz.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2016) Riya, Antony; KAU; Jiji, Joseph
The present study ‘In vitro mutagenesis and evaluation of somatic embryo derived plantlets in cassava (Manihot esculenta Crantz.)’ was conducted in the Department of Plant Breeding and Genetics, College of Horticulture during 2014-15. They study attempted to assess the variability existing among the in vitro derived plantlets of cassava genotypes Sree Jaya and CC1 as well as to generate further variability through in vitro mutagenesis. With the aim to induce variability, in vitro mutagenesis of callus derived from cassava genotypes Sree Jaya and CC1 was attempted earlier in the department. This had resulted in 10 somatic embryo derived plantlets in primary hardening stage and 58 plantlets yet to be transferred for hardening. The above plantlets formed the basic material for field evaluation undertaken in the present study. Sree Jaya and CC1 genotypes were planted as control. Out of the 58 plantlets transferred from the in vitro cultures to hardening, only 34 plantlets survived i.e., the survival was found to be 58.62 per cent. All the ten plants that were already in the primary hardening stage survived. Observations were recorded during field evaluation of the in vitro mutagen treated plants at three, six and nine months after planting as per the descriptor of cassava (Fukuda et al., 2015). The plants varied with respect to qualitative characters like colour of apical leaves, leaf retention, shape of leaf lobe, petiole colour, leaf orientation, colour of stem exterior, extend of root peduncle, shape of tuber, root colour, colour of root pulp and colour of root cortex. Variability was also observed for quantitative characters like length and width of leaf lobe, length to width ratio of leaf lobe, petiole length, distance between leaf scars, height of plant, tuber weight per plant, tuber girth, stem girth, extend of root peduncle, starch content and dry matter content. Among the mutagen treated plants of Sree Jaya none of in vitro mutagen treated plants were found to be superior with respect to tuber yield while in CC1 genotype, six plants yielded better than the control. Sensory evaluation of the tubers produced by in vitro mutagen treated plants as well as control plants was done by twelve panelists to assess consumer perception. The tubers from plant 32 (Sree Jaya; 1.2 % EMS), followed by plant 31 (Sree Jaya; 1.2 % EMS) and plant 42 (CC1; 0.9 % EMS) were most preferred for various sensory attributes evaluated. In vitro mutation being a potential method to induce variability, mutation of callus derived from genotypes was as attempted to create more variants. The callus cultures of Sree Jaya and CC1 genotypes were established as per the protocol standardised by Magaia, (2015). Friable embryogenic calli production was higher in the media MS + 8 mg L-1 2,4-D + 1 mg L-1 NAA + 0.5 mg L-1 BAP using leaf explants. Calli were subjected to physical (γ irradiation at 30- 60 Gy at an interval of 10Gy) and chemical (EMS 0.1 - 0.9 % at an interval of 0.1%) mutagens as advocated by Magaia, (2015). However, regeneration of mutagen treated friable calli was not obtained in both genotypes. Quantum of variability expressed in the in vitro mutated plants of cassava with respect quantitative traits shows the efficiency of in vitro mutagenesis in creating variability in cassava. In vitro mutagenesis is a potential tool in the hands of plant breeder to create variability especially in vegetative propagated crops. The evaluation of in vitro mutagen treated plants in the field showed wide variation with respect to most morphological as well as biometrical traits. All the plants evaluated can hence, be advanced to next generation of evaluation (M1V1) with replication to identify the mutants. From the results obtained on induction of in vitro mutation to create more variants in cassava, it is concluded that the friable callus in both the genotypes need to be cultured in alternate regeneration medium for successful regeneration of somatic embryos.
Open Access
Evaluation of cowpea [Vigna unguiculata (L.) Walp.] genotypes for yield and resistance to pulse beetle [Callosobruchus spp.]
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2017) Thouseem, N; KAU; Beena, Thomas
The present study entitled “Evaluation of cowpea [Vigna unguiculata (L.) Walp.] genotypes for yield and resistance to pulse beetle [Callosobruchus spp.]” was carried out at farmer’s field, Kayamkulam during 2015-2017, with an objective to evaluate cowpea genotypes for yield and resistance to pulse beetle. The study was conducted in two experiments. In experiment-I, yield and resistance to pulse beetle was evaluated in a Randomised Block Design (RBD) with three replications using 30 genotypes collected from different places. Experiment-II was to study the seed morphological and biochemical factors associated with resistance to pulse beetle in five relatively resistant genotypes and five relatively susceptible ones which were identified through experiment-I. The field experiment revealed that the genotype T1 (Ambalappuzha local) showed the highest mean values for days to 50 per cent flowering, length of main stem, pod weight, pod length, number of seeds pod-1, 100 seed weight and crop duration. The maximum yield plant-1 (32.91g) was obtained for the genotype T29 (Sreya) followed byT14 (Alathur local) and T7 (Dhavengarae local), whereas the minimum yield plant-1 (11.07g) was for the genotype T13 (Hridya). Thirteen genotypes were found to be infested under field condition and only very low seed damage via carry over population was noticed. The characters studied were found to be significant for all the genotypes evaluated. The pod weight exhibited the highest GCV (47.73%) and PCV (52.12%). Heritability was high for all the characters except number of primary branches plant-1, number of pods plant-1 and seed yield plant-1 which possessed moderate heritability. GA (% mean) was high for all the characters except crop duration. The association analysis revealed highly significant positive correlation for 100 seed weight, days to 50 per cent flowering, crop duration, number of seeds pod-1, pod girth, and pod length with seed yield both at genotypic and phenotypic levels. The path analysis revealed that 100 seed weight, number of pods plant-1 and number of seeds pod-1 had the maximum positive direct effect on seed yield plant-1. In no choice confinement test under experiment-I, there were significant differences among the genotypes in terms of oviposition, percentage seed damage and percentage seed weight loss. T2 (Kayamkulam local-1) had the least egg load while more eggs were laid on seeds of T29 (Sreya) and T1 (Ambalappuzha local). The highest percentage seed damage and the highest percentage weight loss were recorded for T13 (Hridya) and T27 (Bijapur local) respectively. The lowest percentage seed damage and percentage seed weight loss were observed for the genotype T7 (Dhavengarae local). In the study of seed morphological and biochemical factors associated with resistance under experiment-II, it was found that seed coat texture, seed coat colour and protein content of seeds were found to have no influence on resistance to pulse beetle. However, total phenol content of seed was having significant negative correlation with percentage seed weight loss. An index score was worked out to find out genotypes with good yield and relative resistance to pulse beetle. It was observed that the genotype T7 (Dhavengarae local) had the highest index score followed by T14 (Alathur local). The present study revealed that the genotype T7 (Dhavengarae local) was found to be a good yielder with relative resistance to pulse beetle followed by the genotype T14 (Alathur local). Hence these genotypes can be recommended for future breeding programmes.
Open Access
Genetic divergence in kiriyat (andrographis paniculata nees)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2017) Prathibha, S S; KAU; Arya, K
The study entitled “Genetic divergence in kiriyat (Andrographis paniculata Nees)." was under taken at the College of Agriculture, Vellayani during 2015-17 with the objective to assess the genetic variability present in the natural ecotypes of kiriyat from different regions and identifying the superior ecotypes in terms of herbage yield and quality. Thirty accessions of kiriyat were collected from different parts of India and were evaluated for genetic variability with respect to herbage yield (fresh weight) and quality in terms of total extractives (%). Accession A10 from Aruvipuram showed highest mean values for seedling height (15 DAT), number of primary branches, herbage yield (137.25 g), yield plant-1 (dry herbage yield plant-1) (37.79 g) and total extractives (13.6 %) followed by the A14 (Kottakkal) and A7( Kottakkunnu). The accessions A14 (Kottakkal) and A15 (Nilambur) showed highest mean values for number of secondary branches and number of leaves seedlings-1 (15 DAT) respectively. Mean value for days to 50 percent flowering was least for accession A10. The lowest yield was exhibited by A3 (Coimbatore) accession. Average duration of the plants exhibited ranged between 182.67 and 213 days. The earliest accession was A10 (Aruvipuram) with an average duration of 182.67 days. Seedling height, number of leaves seedling-1, number of secondary branches, leaf length and width, stem girth, leaf/stem ratio, plant height, herbage yield, yield plant-1 and total extractives exhibited high coefficient of variations. Heritability was high for all the characters except number of leaves seedling-1 (15 DAT), herbage yield and yield plant-1 which possessed moderate heritability. GA (% mean) was high for all the characters except plant duration. The association analysis revealed a significant correlation among almost all characters and also with yield. Path coefficient analysis revealed that plant height, herbage yield, number of primary and secondary branches had high positive direct effect on yield. The genetic divergence was studied using Mahanalobis D2 statistics and accessions were grouped into seven clusters. Cluster VII accommodated maximum number of accessions (13) followed by cluster VI (5), cluster V (4), cluster IV (3), clusters III and II (2) and cluster I (1). Highest inter cluster distance was between clusters VI and VII while intra cluster distance was highest for cluster IV. The study revealed that variability existed among the different ecotypes of kiriyat and the ecotype collected from Aruvipuram (A10) was found to be superior in terms of herbage yield and quality followed by ecotypes from Kottakkal (A14) and Kottakkunnu (A
Open Access
Identification of water stress tolerant amaranthus genotypes (Amaranthus tricolor L.) with high yield and quality
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2018) Shahiba, A M; KAU; Beena Thomas
The present study entitled “Identification of water stress tolerant amaranthus genotypes (Amaranthus tricolor L.) with high yield and quality” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2016-2018, with an objective to identify high yielding genotypes of amaranthus with good quality and tolerance to water stress. The study was conducted under two experiments. In the first experiment thirty accessions of Amaranthus tricolor L. available in the Department of Plant Breeding and Genetics and collected from other sources were evaluated for yield under field condition and morphologically described using IBPGR descriptor for the amaranthus. Madhur local (A22) recorded highest yield plant-1(125.926g) followed by Kalliyoor local (A4), Ayyanthole local (A28), Haripad local (A7), Palakkadu local (A2), Anachal local (A6), Aryanadu local (A21), Poonkulam local (A20), Kazhakkuttom local (A9) and Kannara local (A29). In the second experiment, these ten genotypes selected based on the yield were evaluated in a Randomized Block Design (RBD) with three replications during November 2017- December 2017. Water stress was imposed after 5 days of irrigation to water holding capacity to the transplanted seedlings by scheduling the irrigation at a depth of 20mm at 20mm CPE (Cumulative Pan Evaporation). Analysis of variance was calculated for all the characters under study and was found to be significant for all the genotypes evaluated. The mean performance of the genotypes for the characters were studied. The maximum yield was observed for the genotype A22 (Madhur local) followed by the genotype A9 (Kazhakkuttom local), genotype A20 (Poonkulam local) and genotype A2 (Palakkadu local) and the minimum yield was recorded for genotype A4 (Kalliyoor local). The genotype A22 (Madhur local) showed the highest mean values for stem girth, number of branches, length of leaf lamina, leaf to stem ratio, membrane integrity, relative water content, proline content of leaves, vitamin A and lowest oxalate content. The character Vitamin A content registered the highest GCV (41.22%) and PCV (41.25%). High heritability coupled with high genetic advance was observed for leaf width, number of branches, yield plant-1, protein content, fibre content and vitamin A. The yield plant-1was found to be significantly and positively correlated with leaf width, number of branches, yield plot-1, membrane integrity, proline content of leaves and vitamin A both at genotypic and phenotypic levels. Petiole length and percentage leachate were found to be negatively correlated with yield plant-1. Path analysis revealed that number of branches, yield plot-1and proline content of leaves had the maximum positive direct effect on yield plant-1. The results of the present study showed that genotype A22 (Madhur local) was superior in yield performance under water stress condition followed by the genotype A9 (Kazhakkuttom local), genotype A20 (Poonkulam local) and the genotype A2 (Palakkadu local). The genotype A22 (Madhur local) also recorded the maximum stem girth, number of branches, length of leaf lamina, leaf to stem ratio, membrane integrity, relative water content and proline content of leaves with high Vitamin A and low oxalate content. Presence of proline in the leaves might be considered as an important water stress tolerance mechanism.
Open Access
Characterisation of genotypes of orchids
(Department of Plant Breeding and Genetics,College of Agriculture, Padannakad, 2016) Yusuf Abbas; KAU; Sujatha, R
Orchids occur mainly in humid tropics and temperate regions of the world. They are known for their long lasting and bewitchingly beautiful flowers. Out of the nearly 30,000 species of orchids in the world, India contributes around 1200 species. In India, the north eastern region accounts for about 800 species, while the Western Ghats has around 275 species of orchids. Western Ghats is one among the 34 biodiversity hotspots identified in the world. However, due to the continuing loss of habitat, fragmentation, expanding human population and other activities, some of the flora and fauna in this region are included in the highly threatened group, orchids being one among them. Many of the orchids in this region are indiscriminately exploited for the local traditional medicine and for horticulture purpose and thus face the danger of being extinct. Hence the present study was undertaken in order to assess the orchid diversity in selected regions in Central western Ghats and to conserve few genotypes which are threatened. The study on “Characterisation and conservation of promising genotypes of orchids from Central Western Ghats” was carried out at Central Western Ghats and College of Agriculture, Padanakkad, Kasargod, Kerala during 2014-2016. The study was based on the survey carried out in 6 natural habitats of Central Western Ghats namely Aralam Wildlife Sanctuary, Ranipuram Wildlife Sanctuary, Pushpagiri Wildlife Sanctuary, Brahmagiri Wildlife Sanctuary, Talakavery Wildlife Sanctuary and Rajeev Gandhi National Park. The survey revealed that, a total of 9463 accessions of orchids belonging to 70 species classified under 30 genera were present in these habitats. Among these, maximum number of orchid genera was recorded from the Brahmagiri Wildlife Sanctuary (23 genera, 39 species), whereas minimum in the Ranipuram Wildlife Sanctuary (15 genera, 22 species). The diversity analysis was made by using Shannon Index (H') and Simpson Diversity Index (D). The highest diversity was recorded for Bharamagiri Wild Life Sanctuary, with the values of H' - 3.37991 and D - 0.95834, whereas it was lowest for Ranipuram Wildlife Sanctuary with value of H' - 2.540636 and D -0.87597. The preliminary survey indicates higher diversity of orchids in natural forests, which includes rare, endangered species such as Bulbophyllum mysorense, Aerids cripa, A maculosa, Dendrobium crepidatum, Cymbidium bicolor, Rhyncostylis retusa etc. With respect to the species diversity four genera had more number of species compared to other genus, viz., Dendrobium, Bulbphyllum, Hebanaria and Oberonia and maximum number of orchid species were recorded in the genus Dendrobium followed by Bulbophyllum. A total of 46 accessions belonging to14 genera were rescued and established in the orchidarium of which 26 were native to Central Western Ghats; 4 accessions from CoA, Padannakkad in which two accessions were tissue culture plants maintained at Department of Plant Biotechnology (one species each of Dendrobium and Phalenopsis) and 2 accessions from natural habitat of Padanakkad (one species each of Dendrobium and Acampe); 7 accessions from Sikkim (1 Vanda, 1 Coelogyne, and 5 Cymbidium) and 9 accessions were hybrids collected from Bengaluru, comprising of 6 Dendrobiums, 1 Mini Cattleya, 1 Oncidium, and 1 Phalaenopsis. The vegetative and reproductive characters of orchids were recorded based on descriptor available from National Research Centre on Orchids, Sikkim, and were further classified based on their generic characteristics. The vegetative characters reveal variations among the species which could effectively differentiate the accessions from one another. The plant height ranged from 5.9 cm to 126 cm. The maximum plant height and number of leaves were recorded in PDK/ORP-5 (Vanda), the maximum leaf length in PDK/ORP-25 (Cymbidium) and highest number of sprouts in PDK/ORP-25 (Bulbophyllum fischeri). The reproductive characters were recorded at flowering phase for 6 accessions. The flowers were exquisite and showy which exhibit different shapes and colours, the largest flower was recorded in PDK/ORP-16 (Dendrobium hybrid 4) and the longevity of the flower ranged from 8 days (PDK/ORP-45: Acampe) to 26 days (PDK/ORP-20: Dendrobium sp. from Brahmagiri). The molecular characterization was done to study the diversity of the selected 17 accessions belonging to the 14 genera. Out of 30 RAPD primers 10 RAPD primers were selected based on the quality and intensity of amplification. The 10 selected primers produced a total of 399 scorable DNA fragments of high polymorphism that were present among 14 orchids genera, with amplicons in the size range of 300 – 1700 bp. The dendrogram separated the 17 accessions into 6 groups, the range of similarity coefficients was from 0.08 to 0.48 in 14 genera. A total of 20 diagnostic bands were observed, in which OPA 18 produced 6 species specific bands whereas OPA 16 failed to produce any diagnostic band. The intra generic characterization was carried for detecting polymorphism and duplicates, if any, in Vanda and Dendrobium. Nine accessions each of genera Vanda and Dendrobium were separately amplified using 5 selected primers. A total of 192 RAPD bands were produced in Vanda (size range : 150–1450 bp ) whereas 186 RAPD bands in Dendrobium (size range:175–1625 bp) . The range of similarity coefficients for the Vanda was 0.15 to 0.80, and for Dendrobium was 0.15 to 0.70 and the dendrogram separated the accessions into 3 groups each. The Mycorrhizal association study was carried on 14 genera which were subjected to investigations for detecting mycorrhizal association in accessions. The epiphytic species were found to be more associated with mycorrhizae, as their roots are in contact with mosses and debri of organic material. The aerial roots and new roots showed infestation only when they had contact with the substrate. The hyphae and spore of mycorrhizae detected in all samples were of similar type, but they varied in the colonization percentage (60-100%). The study revealed that, ideal period for general growth of the plants under Padanakkad condition is January-February while the sprouting was more during June. Genera like Acampe, Bulbophyllum, Coelogyne, Cymbidium, Dendrobium etc showed faster growth in the orchidarium compared to the rest. Six of the accessions flowered in the orchidarium among which one was a wild collection from Brahmagiri. It is a promising genotype which can be used for breeding purposes as it has the longest flower duration (26 days), bright colour, large petals (45.7mm) & sepals (35.6mm) and it flowered two times within 10 months. Morphological and molecular data revealed that there is no duplication in the collection, even within the same genus.
Open Access
Analysis of inbreeding depression in west coast tall coconut (Cocos nucifera L.)
(Department of Plant Breeding and Genetics, College of Agriculture, Padannakkad, 2016) Chethana, S; KAU; Jayaprakash Naik, B
In nature, coconut is a cross pollinated crop which influences the high degree of variability and heterogeneous population. With the intension of developing inbred line in coconut, the programme was initiated in 1924 by selecting the eighteen WCT palms and developed S 1 generation. The S 1 plants were selfed and sibmated to produce the S 2 progenies in 1960 and the seedlings planted at CRS (RARS), in Pilicode with the replicated trial. This served the present experimental material to characterize and analyze inbreeding depression in S 2 palms and to study the effect of selfing (S 3 ) in selfed and sibmated (S 2 ) families of West Coast Tall (WCT). Vegetative, reproductive and nut characters were recorded in S 2 WCT family. The analysis of variance revealed significant differences among the twelve families of six groups of WCT for all the characters studied. The tallest palms were observed in IVS 2 -2 and IAS 2 -2 and on par with the WCT. The shortest palms were recorded from IIS 2 -1 and IIIS 2 -2 but taller than dwarfs. In general the sibmated families were showing more tall stature indicating heterotic behavior. The IAS 2 -1 and IBS 2 -1 showed average number of functional leaves as tall while IIIS 2 -1 had less number of leaves similar to dwarfs. The petiole length was short in IAS 2 -1 and IAS 2 -2 as well as IIIS 2 -1, IVS 2 -2 and VS 2 -1 indicating an advantageous character of high bearing of nuts with less loss. IIS 2 -1 and VS 2 -1 produced more number of female flowers while IAS 2 -1 and IAS 2 -2 produced less number of female flowers. In IIIS 2 -1 and VS 2 -1, the period of female phase similar to WCT. Thickest kernel was noticed in IBS 2 -1 and VS 2 -2 and less thick in IAS 2 -1. More thickness of kernel is tall palm character and thin meat is dwarf palm trait. Inbreeding depression was studied for S 2 nut yield and its attributes. The family IIS 2 -2 and VS 2 -1 expressed positive inbreeding depression for palm height and internodal length, but no inbreeding depression for stem girth. The leaf characteristics also exhibited positive inbreeding depression in S 2 . The WCTpalms in S 2 generation were characterized primarily based on eight characters separately when selfed and sibmated in S 1 for S 2 generation. In selfed the IBS 2 -1 showed tall characters with highest tall, stouter stem, medium functional leaves, and average female flowers, less setting percentage and low yield, medium nut, high oil percent. Semi tall characters in IIIS 2 -1 which recorded semi tall, stouter stem, average functional leaves, and average inflorescence produced, average female flowers, medium setting percentage, high copra and low oil content. Dwarf characters observed in IIS 2 -1 short, thin stem, high functional leaves, more inflorescence, high female flowers, medium setting percentage, nut yield, copra and oil content high. The S 3 seed nut showed that germination percentage was low in all the families (less than 50%) indicating the operation of deleterious effect of inbreeding in S 3 seed nuts. The semi-tall seedlings were more in selfed and talls in sibmated families of S 3 . The percentage of occurrence of stouter collar girth was more in S 3 (IAS 3 -1, IBS 3 -1, IIS 3 -1, IVS 3 -2, IIS 3 -2, IIIS 3 -2 and VS 3 -2). The leaf production was moderate in all the S 3 seedlings of selfed and four sibmated families (IAS 3 -2, IBS 3 -2, IIIS 3 -2 and VS 3 -2). Both the third and fifth leaves , the length, breadth and petiole length showed moderate values. The germination percentage revealed positive inbreeding depression in all the selfed families of 12 families. High inbreeding depression was noticed in IAS 3 -2, IIIS 3 -2, IVS 3 -2, VS 3 -1 and IVS 3 -1 and the lowest in family 1BS 3 -1 and 1AS 3 -1. Seedling height expressed high inbreeding depression in VS 3 -1. Collar girth didn‟t show inbreeding depression in S 3 . It is an important trait correlated with yield. Both positive and negative inbreeding depression was recorded for total number of leaves produced by the seedlings in S 3 generation. The molecular study using the promising inbreds was done using 10 primers. The analysis by the primers signifies that the family IIIS 3 -1 was unique which was noticed by the 5 primers i.e. OPBA 03, OPAW 19, OPAW 15, OPAW 09 and OPAU 02. The specific bands for dwarfs were noticed from almost all theprimers except for the OPAW 09. While the locus specific to tall have noticed from the primer OPBA 03 and OPAU 03. The specificity to the samples has also been noticed from some primers which was the WCT specific (OPAU 03), CGD (OPAW 15 and OPAW 08), IAS 3 -1 (OPAW 12, OPAW 13 and OPAW 08), IBS 3 - 1 (OPAW 19 and OPAU 03) and IIIS 3 -1 (OPAW 19). The coloured types IAS 3 -1 and IBS 3 -1 were highest and observed as on par with the WCT which were evidently proved by the primer OPBA 03 and OPAW 19. Among the primers, highly significant bands between the tall and dwarf was noticed by the OPBA 03 and OPAU 03. It is evident from the studies that the selfing of WCT palms would reduce vigour and possible to develop inbred lines which could be used for the production of hybrids for higher productivity.
Open Access
Physico-chemical and molecular characterization of grain quality of traditional rice varities
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2016) Jeena George; KAU; Jayalekshmy, V G
The present study entitled “Physico-chemical and molecular characterization of grain quality of traditional rice varieties” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, during 2014 - 2016, for assessing the land races of rice for physical and chemical parameters associated with grain quality and molecular characterization with SSR (Simple Sequence Repeats) markers specific to quality traits. Dehusked grains of twenty traditional rice varieties including medicinal rice Njavara were assessed for physical, chemical and cooking quality characteristics. Significant variations were observed among the varieties for all the traits evaluated. The kernel length of the varieties ranged from 4.00 mm (Gandhakasala) to 6.91 mm (Chennellu). The kernel length/breadth ratio ranged from 1.60 to 2.91. Based on the kernel length/breadth ratio, the grain shape of selected varieties was classified under medium and bold types. The linear elongation ratio for the varieties ranged from 1.11 to 1.60 and breadth wise elongation ratio ranged from 1.01 to 1.94. The variety Karimbalan took maximum time for cooking (52 minutes) and the variety Jeerakasala took the minimum time (31 minutes). Chemical characterization showed that, amylose content of the varieties ranged from 12.32% (Jeerakasala) to 29.82% (Cheruvirippu). The variety Njavara Veluthath recorded maximum protein content (13.57%) and the varieties like Cheradi, Marathondi and Thondi showed the minimum (8.90%). The Iron and Zinc content of the varieties ranged from 45.45 to 311.54 mg/kg and 27.88 to 102.41 mg/kg respectively. The variety Karimbalan recorded maximum Iron and Zinc content. The carotene content of the varieties ranged from 0.14 to 0.56 mg/lOOg. The minimum value was recorded for Mullan Kayama and maximum for Njavara Veluthath. Correlation analysis showed positive significant relationship between Iron and Zinc content. The amylose content also showed positive but non significant relationship with volume expansion and optimum cooking time. In molecular characterization, SSR marker RM535 linked to QTL (Quantitative Trait Loci) for Iron and Zinc content was detected in thirteen varieties. The marker RM190 linked with Wx gene locus associated with amylose content was detected in seventeen varieties and the marker RM520 linked to QTL for protein content was detected in all the varieties. The varieties identified as rich source of genes linked to quality traits can be used for the transfer of these genes to the cultivated varieties for quality improvement through marker assisted selection. The present investigation has proven that traditional rice varieties are rich in micronutrients and protein. The varieties like Njavara Veluthath and Orumundakan rich in protein can be utilized as donors for this character in further breeding program. The varieties which are superior in Iron and Zinc content like Karimbalan and Veliyan can be utilized as lines for biofortification programs which can nourish the growing population and tackle the “hidden hunger”.

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