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ThesisItem 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, FranciesExploiting 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.ThesisItem 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, KThe 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.ThesisItem Open Access Combination breeding for high protein cowpea (Vigna unguiculata L. Walp)(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2015) Sarath, P S; KAU; Jiji, JosephCowpea (Vigna unguiculata L. Walp) is one of the most important legume crops grown in India. It is a versatile pulse crop owing to its nutritional value, weed smothering nature, drought tolerant characters, soil restoring properties and multi-purpose uses. Protein deficiency has been reported to be one of the main nutritional problems in the developing world. About one billion people are reported to be suffering from protein deficiency and malnutrition worldwide. Studies have revealed that protein content in cowpea grain ranges between 18 to 40 per cent depending on the genotypes. Identifying high yielding varieties of cowpea with high protein content will not only contribute to food security and alleviate poverty but could also contribute to the alleviation of protein deficiencies. Review on the earlier research pointed to poor emphasis on the genetic improvement of cowpea for improved protein content. Hence, the present study was envisaged to combine the high protein trait with high yielding genotypes. The study was grouped under three experiments, i) Evaluation of cowpea genotypes, ii) Hybridisation of the selected genotypes in line x tester design, iii) Evaluation of F1 hybrids. The experiments were conducted at College of Horticulture, Kerala Agricultural University, Vellanikkara during 2014-2015. All the crop management practices were followed as per KAU (2011). Evaluation of cowpea genotypes revealed that there was wide variability for all the traits studied except branches per plant among bushy and semi trailing types of cowpea. In trailing type, variability was observed for plant height, number of pods per plant, pod weight grain yield per plant and seed protein content. Among the twenty two genotypes evaluated, ten genotypes that exhibited a protein content of above 25 per cent were selected for hybridization programme. The selected genotypes (Vellayani Jyothika, Bhagyalakshmi, Anaswara, Kanakamony, Lola, Vyjayanthi, AV-5, PKB-3, PKB-4 and Sharika) were hybridized in line x tester (6 x 4) design. High magnitude of phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability and genetic advance was observed for plant height, grain yield per plant and length of pods were observed in parents and hybrids suggesting scope for genetic improvement of these traits through selection. Seeds per pod and protein content exhibited low PCV and GCV but high heritability and low genetic gain, indicating that these traits were governed by non-additive gene action and therefore breeding method other than simple selection is required. Combining ability analysis revealed that higher magnitude of specific combining ability (SCA) variances than the general combining ability (GCA) variances for the traits like pods per plant, length of pod, test weight, grain yield per plant and seed protein content indicating preponderance of non-additive gene action in the inheritance of these traits. Higher estimates of GCA variances over SCA variances for plant height, days to flowering, days to first harvest, days to last harvest, pod-weight and seeds per pod implies the preponderance of additive gene action in controlling these traits. The hybrids were ranked based on mean value, sca effects and estimates of heterosis for the traits like days to flowering, pods per plant, seeds per pod, test weight, grain yield per plant and protein content. Four hybrids with the lowest scores were selected. Hybrids H2 (Vellayani Jyothika x PKB-3), H10 (Anaswara x PKB-3), H11(Anaswara x PKB-4) and H12 (Anaswara xSharika) were found to be the most promising. The transgressive segregants with high yield and protein content can be identified on further evaluation of the segregating population from the above hybridsThesisItem 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, JosephThe 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.ThesisItem 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, ThomasThe 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.ThesisItem 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, KThe 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 (AThesisItem 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 ThomasThe 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.ThesisItem 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, NamboodiriThe 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.ThesisItem 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 AbrahamIn 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.
