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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
Development of F1 hybrids in okra [Abelmoschus esculentus L. Moench]
(Department of Plant Breeding & Genetics, College of Agriculture,Padannakkad, 2019) Jaseera, U A; KAU; Raji Vasudevan, Namboodiri
The project entitled “Development of F1 hybrids in okra [Abelmoschus esculentus L .Moench]” was carried out at the Instructional farm, College of Agriculture, Padannakkad during April-July 2019 to study heterosis and combining ability. The experiment was carried out in two parts. In part I, six diverse parents viz. AE5, AE16, AE18, AE20, AE30 and Salkeerthi were raised in a crossing block. They were crossed in half diallel fashion and 15 F1 hybrids were produced. In part II, the hybrids were evaluated along with their parents and checks in a randomized block design with 26 genotypes and three replications. Arka Anamika and Salkeerthi were used as OPV checks and Manjima and Arka Nikita as F1 hybrid checks. Parents of Manjima viz. Gowreesapattam local and IC282257 were also included as checks. Half diallel analysis was adopted for combining ability analysis. Relative heterosis, heterobeltiosis and standard heterosis using F1 hybrid Arka Nikita as standard check were worked out for all the characters. The estimation of heterosis revealed significant standard heterosis in the hybrids in desirable direction for growth, earliness and fruit traits. Three hybrids AE30 x AE18, AE30 x Salkeerthi and AE20 x AE30 showed highly significant positive standard heterosis for plant height. Three hybrids AE30 x Salkeerthi, AE30 x AE5 and AE18 x Salkeerthi showed highly significant positive standard heterosis for primary branches per plant. Two hybrids AE16 x AE5 and AE18 x AE5 showed highly significant negative standard heterosis for internode length. Two hybridsAE16 x Salkeerthi and AE20 x Salkeerthi showed highly significant negative standard heterosis for days to flowering. One hybrid AE18 x AE5 showed highly significant negative standard heterosis for days to 50% flowering. Five hybrids AE16 x AE30, AE16 x AE18, AE16 x AE5, AE20 x AE18, and AE30 x AE18 showed highly significant negative standard heterosis for node of fruit set. None of the hybrids showed significant positive standard heterosis for number of fruiting nodes. For fruit length AE20 x AE18 and AE20 x Salkeerthi showed significant positive standard heterosis. Three hybrids AE16 x AE30 AE5 x Salkeerthi and AE30 x AE5 showed significant positive standard heterosis for fruit girth. For fruit weight the hybrids AE30 xAE5, AE18 x AE5, AE20 x Salkeerthi, and AE20 x AE18 showed significant positive standard heterosis. None of the crosses showed significant positive standard heterosis for number of fruits per plant, marketable fruits per plant, marketable fruits per plant and yield per plant. The hybrid AE30 x Salkeerthi showed significant positive standard heterosis for mucilage content. Analysis of variance for combining ability revealed significant difference among the genotypes for all traits except fiber content, indicating sufficient variability for selection. The gca variance/ sca variance ratio indicated preponderance of non-additive gene action for all traits. None of the cross combinations exhibited high significant combining ability effects in desirable direction for all characters studied. The association of sca effects of outstanding crosses with gca effects of parents for each of the characters revealed that the high specific combiners involved high x high, high x low and low x low general combiners as parents. A combination of mean performance and gca effect was used to identify best parents and it revealed AE16, AE30 and AE20 as better performing parents for maximum number of characters. Even though the mean performance of AE16 was higher for fruit weight, number of fruiting nodes, yield per plant and marketable yield per plant, it was a poor general combiner for characters viz. number of fruiting nodes, fruit weight, and yield per plant compared to AE20 and marketable yield per plant compared to AE30. High gca effects for fruit yield in AE20 and AE30 were associated with good gca effects for number of fruits per plant and fruit weight. The parental lines AE20 and AE30 performed well even they were affected by yellow vein mosaic disease and fruit and shoot borer. Hence they can be used in further breeding program for higher yield. The parental line AE20 was the high general combiner for all of the three earliness attributes such as days to first ﬂowering, days to 50% ﬂowering, and node of fruit set, indicating its potential for exploiting earliness in okra. Promising crosses were identified based on mean performance, sca effect and standard heterosis for important growth and yield characters. None of the hybrids exhibited significant standard heterosis in the desirable direction for yield. Hence the hybrids showing lower value of negative standard heterosis were selected. The four better performing crosses identified were AE30 x AE5, AE20 x AE5, AE20 x Salkeerthi and AE30 x Salkeerthi. All these four crosses were good performers for marketable yield even when they were affected by yellow vein mosaic disease and shoot and fruit borer. In addition, these crosses showed good performance for few other yield contributing characters also. The cross AE30 x AE5 performed well for fruit weight, number of fruiting nodes and yield per plant. The cross AE20 x AE5 showed good performance for number of fruits per plant, marketable fruits per plant and yield per plant. AE20 x Salkeerthi was a good performer for fruit weight and fruit length. AE30 x Salkeerthi was good performer for plant height, primary branches per plant, internode length and mucilage content.
Open Access
Genetic analysis of yield and quality in fodder cowpea (Vigna unguiculata (L.) Walp)
(Department of Plant Breeding & Genetics, College of Agriculture,Vellayani, 2019) Praveena, V S; KAU; Mareen Abraham
In the present study, "genetic analysis of yield and quality in fodder cowpea {Vigna unguiculata (L.) Walp)", evaluation of different fodder cowpea accessions were done to assess the variability in the available population to identify the good performers for forage yield and quality. Based on the morphological and molecular characterization superior parents were selected for crop improvement through hybridization to develop superior cross combinations. The salient features of the study are discussed below. Significant variation was observed for all tlie fourteen characters studied, the range of mean values observed refers to the phenotypic and genotypic variability present in the base population. High genotypic and phenotypic coefficient of variation was observed for number of primary branches plant ', number of leaves plant ', leaf area index, green fodder yield plant ', dry matter yield plant"', leaf fresh weight plant"', stem fresh weight plant"', leaf dry weight plant"', stem dry weight plant"' and crude fiber content. High heritability and genetic advance for crude fiber content, crude protein content, leaf area index, leaf dry weight plant ', dry matter yield plant"', stem dry weight plant"', number of leaves plant"', stem dry weight plant'', number of leaves plant"', stem fresh weight plant"', leaf fresh weight plant*' and green fodder yield plant"'. Green fodder yield and dry matter yield had significant positive phenotypic and genotypic correlation with leaf fresh weight plant"', followed by stem fresh weight plant"', stem dry weight plant"', dry matter yield plant"', leaf dry matter plant"', number of primary branches plant"' and number of leaves plant"'. The thirty fodder cowpea genotypes were grouped into eleven clusters. Maximum contribution to divergence was shown by leaf fresh weight plant"' followed by crude fibre content, stem dry weight plant"', leaf area index, dry matter yield plant*', number of leaves plant"', crude protein content and green fodder yield plant"'. Selection index was hi^est for IT-37154999-38 and least for IC- 202804. The genotypes were ranked for characters green fodder yield, crude protein content, crude fibre content and selection index. Based on this and maximum inter cluster distance eight genotypes CO-8, MFC-09-1, IC-1061, IC- 39916, IC-97767, lC-38956-1, 17-37154999-38 and Pant Lobia-2 were selected for further hybridization programmes. Molecular characterization revealed two clusters (I and II) with 0.34 per cent similarity. The statistical cluster diagram from value and dendrogram from molecular characterization were not similar. But the eight parents selected had considerable difference in dendrogram with minimum difference between parents IT-38956-1 and IT-37154999-38. Diallel analysis is one of the techniques used to find the genetic makeup. Gca variance was greater than sea variance, for all characters except for days to first flowering and crude protein content, indicating predominance of additive gene action for most of the characters. Days to first flowering and crude protein content had non-additive gene action. Presence of heterosis also shows the ability of the parents to combine well in a hybridization programme. Superior expression of Fi may be due to fixable (additive) type of gene action and non-additive type of gene action. Thus combining ability and heterosis helps in identifying desirable cross combinations. Twenty eight hybrids from eight parent were evaluated for combining ability in diallel mating design without reciprocals. Relative heterosis and heterobeltiosis were calculated for different traits. Gca variance was greater than sea variance, indicating predominance of additive gene action. P4, Ps and Pe were good general combiners among eight parents for plant height. Gca variance was greater than sea variance, indicating predominance of additive gene action in green fodder yield and dry matter jdeld. Ps, Pe, P? and Ps were good general combiners for green foddra* yield, dry matter yield, leaf fresh weight, stem fresh weight, crude protein content and crude fibre content. Nineteen of the hybrids were good specific combiners for I7f7^^ ni green fodder yield. Seventeen hybrids were good specific combiners for lower crude fibre content. Pi X ??, P2X P7, P5X P7 and P5X Pg were selected based on high green fodder yield, dry matter yield, higb protein content and low fibre content for raising F2 population. F2 families of these four hybrids exhibited differences among the progenies for different characters studied. Progenies of hybrid PiX P7 was identified as the best superior cross combinant useful for further improvement for superior variety development.
Open Access
Alleilic difference in the putative gene ipk1 sequence and phytic acid (INSP6) content in Black Pepper
(Department of Plant Breeding & Genetics, College of Agriculture, Padannakkad, 2019) Gladish Mary, Joy; KAU; Sujatha, R
Black pepper (Piper nigrum L.) is one of the world’s highly demanded and most traded spices with high medicinal and therapeutic values. A unigene pnc135 (995 bp) was developed by the Expressed sequence tags data obtained by next generation sequencing. This unigene was found to show similarity with ipk1 gene reported in other crop species which encodes for inositol pentakisphosphate-2 kinase enzyme (Unpublished data, Sujatha,R.). This enzyme is involved in the phosphorylation of inositol pentakisphosphate to inositol hexakisphosphate or phytic acid (InsP6), last step in the biosynthetic pathway of phytic acid. This unigene was later partially sequenced (1072 bp) towards the 3’ end by directional genome walking by Giridhari (2017). Phytic acid functions as the major storage form of phosphorus in seeds, cereals and legumes possessing significant benefits including signalling, plant communication, messenger RNA transport etc. However, phytic acid also acts as an anti-nutrient in animals as its chelating property will cause malnutrition in organisms and also leads to environmental pollution due to phosphorus excretion by non-ruminant animals. Therefore researchers are finding ways to create ipk1 mutants for either to decrease or increase the phytic acid content in organisms. However the genetic information about the black pepper crop remains very limited and the metabolic pathways and the genes related to it are also poorly understood. So in this study entitled “Allelic difference in the putative gene ipk1 sequence and phytic acid (InsP6) content in black pepper (Piper nigrum L.)”, the objective was to find out the flanking region towards the 5’ region of pnipk1 gene fragment (1072 bp) reported earlier by Giridhari (2017), to identify the allelic differences in pnipk1 gene in 10 black pepper genotypes and to estimate and quantify the phytic acid content in these 10 black pepper genotypes using polyacrylamide gel electrophoresis (PAGE). Genomic DNA was isolated from Panniyur 1 variety of black pepper and used it for the whole genome amplification by Rolling Circle Amplification method using Phi 29 DNA polymerase and walker adaptors (WA1, WA2, WA3 and WA4) reported by Reddy et al. (2008). After whole genome amplification, genome walking using primer combinations of walker primers, locus specific primers and nested locus specific primers were performed to find out the flanking region towards the 5’ region of pnipk1(1072 bp) gene fragment of black pepper. The walker primers (WP1 and WP2) used for genome walking were same as that of reported in Reddy et al. (2008) and the locus and nested locus specific primers were designed on the basis of pnipk1 gene fragment (1072 bp) sequenced by Giridhari (2017). From the nested PCR amplification four products, two amplicons, A1R3 and A4R3, each at two different temperatures viz., 51.6⁰Ϲ and 56.8⁰Ϲ were obtained and sequenced. On assembling the sequences a contig of length 523 bp was obtained towards the 5’ region of pnipk1 gene fragment and this showed similarity to ipk1 gene in other crops. This 523 bp contig was assembled with ipk1 gene fragment (pnipk1-1072 bp) to get a total length of 1535 bp. The newly assembled ipk1 gene sequence (pnipk1-1535 bp) was analysed in ORF finder for the coding region and found an Open Reading Frame (ORF) with 645 bp encoding for 214 amino acids. Phylogenetic analysis of the sequence and translated amino acid sequence showed closer evolutionary relationship with that of Dendrobium catenatum. Primers were designed based upon the pnipk1 gene sequence (1535 bp) to amplify the genomic DNA of Panniyur 1 and other 10 black pepper genotypes. The selected 10 genotypes were Panniyur 5, Panniyur 7, Chettanvally, Kottanadan, Karimunda 7, Thottamundy, Karimunda kuttyatur, Payyanganam 2, PRS 160 and Chumala. Amplification of pnipk1 gene (1535 bp) was obtained from genomic DNA of Panniyur 1, Panniyur 5, Panniyur 7 and Karimunda 7 with the expected of amplicon size indicating a similar sequence among these genotypes. Whereas amplification was not obtained in genomic DNA in rest of the genotypes showing allelic variation is present for ipk1 gene in these genotypes. To estimate and quantify the phytic acid content in Panniyur 1 and 10 black pepper genotypes, polyacrylamide gel electrophoresis (PAGE) was performed. Phytic acid was extracted from black pepper varieties same as that of selected for allelic difference analysis in ipk1 gene (pnipk1-1535 bp). The samples were loaded with phytate standards and band intensities of each concentration were determined with Gelquant.NET. The values of phytic acid in black pepper genotypes were estimated by the standard curve. The quantity of phytic acid in samples are: Panniyur 5 with 502.5nmoles/g, Panniyur 7 with 367.5nmoles/g, Chettanvally-511.5nmoles/g, Kottanadan-463.5nmoles/g, Karimunda7- 387nmoles/g, Chumala-201nmoles/g, Karimunda kuttyatur-637.5nmoles/g, Payyanganam 2-196.5nmoles/g and Panniyur 1- 275 nmoles/g, Thotamundy- 198nmoles/g, PRS 160-697.5nmoles/g. Based on the phytic acid content in the black pepper genotypes, they can be classified into low (<210 nmoles/g), medium (210-510 nmoles/g) and high (>510 nmoles/g) phytic acid content. The ipk1 gene fragment (pnipk1-1535 bp) was amplified in the genotypes Panniyur 1, Panniyur 5, Panniyur 7 and Karimunda 7. These genotypes all came under the category of medium phytic acid content group. The study resulted in sequencing a total of 1535 bp long segment of ipk1 gene black pepper variety Panniyur 1 and analysing the presence of allelic variation in ipk1 gene and phytic acid content in selected black pepper genotypes.
Open Access
Marker assisted selection for heat tolerance in rice (Oryza sativa L.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2019) Silpa, V; KAU; Sindhumole, P
Rice is highly susceptible to heat stress, particularly during the reproductive and ripening stages. In the major rice growing tracts of Kerala viz., at Palakkad, Kole and Kuttanad, the temperature tends to rise up to 40 ºC or more during the second/third crop. Consequently, high temperature induced sterility has become a serious problem. To tackle this, high yielding varieties coupled with heat stress need to be developed. As most of the prevalent high yielding rice varieties in Kerala including Uma are highly susceptible to heat stress. It is therefore, essential to impart heat tolerance to such varieties which are cultivated to a very large extent. Marker assisted selection (MAS) has been identified as a dependable, reproducible and time saving strategy to confirm the presence of desirable gene and to quicken the breeding cycle. A study conducted for the identification of SSR markers linked to the genes for heat tolerance in rice through bulked segregant analysis approach using F3 population of the cross Uma x N22 revealed that microsatellite marker, RM5749 was tightly linked to spikelet fertility trait under heat stress. The F4 population (59 nos.) raised from seven F3 lines that were found tolerant to heat stress comprised the base population for the present study. They were characterised morphologically and heat tolerance was scored under natural heat stress in the field conditions based on IRRI spikelet fertility classification. In the 26 F4 lines that registered more than 75 per cent spikelet fertility, foreground selection was done using RM5749. All the 26 F4 plants registered an amplicon corresponding to the heat tolerant parent N22. Background selection of these 26 lines was done using 35 markers found polymorphic between the parents Uma and N22. Seventy five F5 plants were evaluated for morphological characters. Among these, nine F5 plants (Plant nos.16.1.4, 16.1.5, 16.1.6, 31.2.3, 31.2.4, 31.2.5, 31.5.1, 31.6.6, and 31.6.9) with high spikelet fertility (60-70 %) were selected and genotyped using RM5749. These lines were further genotyped using the 35 polymorphic background markers. All the nine F5 plants recorded 54-64 % similarity to Uma genome. The highest spikelet fertility percentage was observed in plant no.16.1.5 (70.78 %) while the highest recovery of the parental genome of Uma was found in plant no. 31.2.5 (64.28 %). Backcrossing of the seven selected heat tolerant lines of F4 (lines 12, 13, 15, 16, 31, 41, and 45) with Uma as male parent resulted in production of BC1F1 seeds. However, the seedlings raised from these seeds did not survive under field conditions. The results obtained thus indicated that the nine lines selected in the present study are to be evaluated in further generations morphologically inorder to isolate genotypes with tolerance to heat stress.
Open Access
Development of stabilised population of cowpea segregants(Vigna unguiculata (L.) walp.) with high protein content and grain yield
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2019) Ashni Varghese; KAU; Jiji Joseph
Cowpea (Vigna unguiculata (L.) Walp.) is an important pulse crop providing good source of protein and often referred to as poor man’s meat. It is a versatile crop, of which seeds are utilised as pulse, green pods as vegetable, leaves as forage and helps in restoring soil fertility. Many reports have indicated protein content of more than 30 per cent in certain cowpea genotypes, but at the cost of yield. Hence, the present study was proposed to develop cultures with high grain yield and protein content. The present study was conducted at Department of Plant Breeding and Genetics, College of Horticulture during 2017-2019. Twenty three lines with high yield and protein content in the F3 generation of two cowpea crosses H10 (Anaswara X PKB 3) and H11 (Anaswara X PKB 4) identified in previous studies formed the working material. These lines were evaluated in F4, F5 and F6 generations and pedigree selection was performed to select superior plants. Observations were recorded on 12 characters viz. plant height, number of branches, days to first flowering, days to first harvest, days to last harvest, number of pods per plant, length of pod, pod weight, number of seeds per pod, hundred seed weight, grain yield per plant and protein content. The F4 generation of both the crosses exhibited lower mean value for most of the characters than the parent Anaswara, but recorded moderate to high variance and range. Higher mean value was observed for days to first flowering, first harvest, last harvest, number of branches and protein content. Genetic parameters indicated that GCV was moderate for length of pod, number of seeds per pod, and hundred seed weight and high for grain yield per plant. High heritability coupled with moderate to high genetic advance was recorded for number of pods per plant, number of seeds per pod, hundred seed weight, and grain yield. Correlation studies in F4 generation revealed that grain yield was positively correlated with plant height, number of branches per plant, number of pods per plant, length of pod, pod weight, number of seeds per pod and test weight. There was non-significant correlation between grain yield and seed protein content. Further path analysis confirmed that high positive direct effect on grain yield was given by pods per plant, number of seeds per pod and hundred seed weight. Based on these observations, characters like number of pods per plant, hundred seed weight and number of seeds per pod were simultaneously included along with grain yield for setting selection criteria to select superior individual plants. Based on these set criteria, 13 individual plants from cross H10 and 10 plants from cross H11 were selected and forwarded to F5 generation. In F5 generation, mean values for number of branches, number of pods per plant, number of seeds per pod and protein content were higher than that of Anaswara with sufficient variance and range. GCV was moderate for number of branches, length of pod, pod weight, hundred seed weight and grain yield per plant. High heritability with moderate to high genetic advance was recorded for number of pods per plant, length of pod, pod weight, number of seeds per pod, hundred seed weight and grain yield. Based on the segregation pattern observed, the plants were grouped into two different categories - one with medium long pods and small seeds closely packed within the pod and the other type with long fleshy pods and bold seeds. Hence, separate selection criteria was developed for both the types comprising of characters like number of pods, number of seeds per pod, pod length, hundred seed weight, grain yield and protein content. Based on these set criteria, five individual plants from cross H10 (one type 1 and four type 2) and 17 plants from cross H11 (five type 1 and twelve type 2) were selected and forwarded to F6 generation. In F6 generation, mean value was higher than Anaswara for number of pods per plant but lower for plant height, days to first flowering, days to first harvest, days to last harvest, pod length and hundred seed weight. For other characters, mean value was comparable to Anaswara. Moderate GCV value was recorded for length of pod, pod weight and hundred seed weight. High heritability with high genetic advance was recorded for length of pod, pod weight and hundred seed weight. Separate selection criteria was developed for the two categories of plants and total five individual plants were selected, one from cross H10 and four from cross H11. The selected plants from F6 generation were subjected to organoleptic evaluation to find its suitability to be used for vegetable purpose. Three plants of type 2 and one plant from type 1 were found promising. The identified lines, H11-3.9-1-7-13-7, H11-3.9-1-1-18-13, H11-49.7-1-8-10-15, H10-71-16-1-9-15-12, and H11-2-20-3-14-16-12 can be evaluated in replicated yield trials and tested for stability over locations and seasons
Open Access
Genetic evaluation of F2 generation for yield and water stress tolerence in upland rice
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2018) Ivy Mary, Rajan; KAU; Lekha Rani, C
The present study entitled “Genetic evaluation of F2 generation for yield and water stress tolerance in upland rice” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2016-2018. The objective was to evaluate the pattern of variability in F2 for yield and yield contributing traits under upland and drought situations and to select superior segregants combining drought tolerance and high yield. The study material included four parents and three F2 populations selected from the Ph.D project entitled “Genetic analysis of drought tolerance in rice (Oryza sativa L.)”. The study comprised of two experiments .In experiment- I, the parents and F2 segregants were raised under rainfed upland condition exposed to natural stress. Among the F2 populations, Vaishak x Harsha (T6) recorded the highest mean grain yield plantˉ1 (38.45g – 48.15g) and lowest mean spikelet sterility (7.76%-21.18%). T6 recorded the highest mean values for number of productive tillers plantˉ1 (9 - 16) and leaf area index (mean: 1.67). Vaishak x Vyttila 6 (T5) recorded the highest mean values for number of spikelets panicleˉ1 (149 - 178), harvest index (44.88% – 48.15%) and proline content (mean: 0.29mg g−1). Thottacheera x Harsha (T7) recorded the highest mean values for chlorophyll(mean: 1.78mg g−1) and leaf soluble protein content (mean: 9.36mg g−1). The data obtained was subjected to transgressive segregation analysis and in T5 more than 50 percent positive segregants were observed for number of productive tillers plantˉ1, spikelet sterility, number of spikelets panicleˉ1 and panicle length. T6 recorded high percentage of positive segregants for number of productive tillersˉ1, grain yield plantˉ1, plant height and spikelet sterility. In T7 percentage of positive segregants were the highest for spikelet sterility and number of productive tillers plantˉ1. Dendrogram drawn on the basis of squared Euclidean distances classified the genotypes into four clusters. Cluster I -T1,T5,T6, cluster II- T4, cluster III -T2,T7 and cluster IV-T3. In experiment II, another set of parents and F2 segregants were grown under rainshelter imposing reproductive stage moisture stress. Irrigation was given at 20mm depth once in seven days from panicle initiation stage onwards. Among the F2 segregants, T5 recorded the highest mean values for grain yield plantˉ1 (11.80g – 18.88g), number of spikelets panicleˉ1 (128 - 174), grain weight panicleˉ1 (2.60g – 4.33g ), harvest index (42.44 % - 68.13%) and proline content (mean: 0.57) and the lowest for spikelet sterility (5.50% - 22.27%). T6 recorded the highest mean value for panicle length (19.60cm – 27.50cm). T7 marked the highest mean values for number of productive tillers plantˉ1 (3 – 7), chlorophyll (mean: 1.28mg g−1) and leaf soluble protein content(mean: 8.82mg g−1) and leaf area index (mean: 0.71). In T5, more than 50 percent of positive segregants were recorded for grain weight panicleˉ1, number of filled grains panicleˉ1 and number of spikelets panicleˉ1. T6 recorded higher percentage of positive segregants for straw yield plantˉ1 whereas T7 recorded the highest positive segregants for 1000 grain weight. On the basis of dendrogram drawn the genotypes were grouped into four clusters. Cluster I -T4 and T6, cluster II-T2,T7, cluster III - T3, T5 and cluster IV - T1. Among the F2 segregants, Vaishak x Harsha (T6) performed well under upland condition whereas Vaishak x Vyttila 6 (T5) performed well under stress. The high yielding variety Vaishak released for uplands might have transferred its superior yield characters to the progeny. The transgressive segregants with favourable traits thus obtained can be effectively utilised for selecting superior genotypes combining drought tolerance and high yield.

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