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ThesisItem Open Access Breeding yard long bean(Vigna unguiculata subsp.sesquipedalis (L.) Verdcourt) for anthracnose resistance through conventional and molecular marker analysis(Department of Vegetable Science College of Agriculture ,Vellayani, 2022) Merin Elza George; Sarada,SThe study entitled ―Breeding yard long bean (Vigna unguiculata subsp. sesquipedalis (L.) Verdcourt) for anthracnose resistance through conventional and molecular marker analysis‖ was carried out at the Department of Vegetable Science, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala, during 2019-2022. The objective of the study was to identify molecular marker(s) linked with anthracnose disease resistance in the F2 segregating population of yard long bean, using bulk segregant analysis to enable marker assisted selection along with conventional breeding. The study was undertaken in six experiments. In experiment I, 50 genotypes of vegetable cowpea collected from different parts of India, including the released varieties of SAUs and ICAR institutes were screened against the most virulent isolate of Colletotricum gloeosporioides through artificial inoculation. Among the 50 genotypes tested, VU 53, with semi-trailing growth habit was found to be highly resistant with disease severity of 3.67 ± 0.13 %. Three susceptible, high yielding long podded varieties viz., KAU Deepika, Vellayani Jyothika and Githika, selected as female parents were crossed with VU 53, the most resistant genotype as male parent for the development of three hybrids. In experiment II, two crossing blocks were laid to produce the seeds of three hybrids and their F2 progenies. The three hybrids were evaluated along with the parents under replicated trial in the main field for trailing nature, yield and quality in experiment III. Significant variation was noticed on mean performance of yard long bean parents and hybrids for most of the characters studied. Earliest flowering was observed in KAU Deepika x VU 53 (57.33 ± 0.57 days) and delayed flowering in Githika x VU 53 (71.66 ± 1.15 days). Among the hybrids, the highest pod length was recorded in KAU Deepika x VU 53 (24.50 ± 1.00 cm), while the Vellayani Jyothika x VU 53 had the maximum pod girth (2.90 ± 0.10 cm). Maximum pod weight and pods per plant was recorded in KAU Deepika x VU 53 (19.22 ± 0.58 g and 79.33 ± 0.59 respectively) among hybrids. The cross Vellayani Jyothika x VU 53 (16.55 ± 0.20 g) exhibited maximum seed weight. Among the three hybrids, KAU Deepika x VU 53 (1416.00 ± 126.09 g) recorded the highest yield per plant and was on par with Githika x VU 53 (1343.33 ± 75.06 g). Among the hybrids, KAU Deepika x VU 53 (67.85 ± 0.96 days) was significantly superior for days to harvest. The longest duration among hybrids was observed in KAU Deepika x VU 53 (126.56 ± 0.37 days) and the shortest duration was recorded in Vellayani Jyothika x VU 53 (121.31 ± 0.58 days). High heritability and genetic advance was recorded for vine length, days to first flowering, pod length, pod weight, pods per plant, yield per plant, yield per plot, hundred seed weight and keeping quality. Yield per plant had significant positive phenotypic and genotypic correlation with pod weight, followed by pods per plant, length of terminal leaf, seeds per pod, pod length, crop duration, keeping quality and days to harvest. Pods per plant could be considered as the most important yield trait for enhancing the yield in yard long bean because of its high, positive correlation and direct effect with yield per plant along with high heritability and genetic advance. In experiment IV, parents, three hybrids and F2 progenies were evaluated for resistance to natural incidence of C. gloeosporioides in the main field, as unreplicated trial and without any plant protection measures. All the three F1 were found to be field tolerant. Out of 175 F2 plants of the cross KAU Deepika x VU 53, 164 plants were susceptible and 11 were resistant. In the case of Vellayani Jyothika x VU 53, 175 plants were susceptible among the 187 individual F2 progenies observed. Similarly, in the cross Githika x VU 53, 188 plants were susceptible while 12 plants were found to be symptomless. The F2 progenies of the high yielding hybrid KAU Deepika x VU 53 were evaluated for resistance to C. gloeosporioides through artificial inoculation in experiment V. Out of 196 plants, 185 plants were found to be susceptible whereas 11 plants were resistant which could be utilized in marker assisted breeding programme. The segregation for anthracnose resistance in F2 plants was in the ratio 15:1 (185 susceptible plants out of 196), which suggests that the inheritance of anthracnose resistance may be controlled by two recessive genes. Bulked segregant analysis was done using the DNA from the resistant parent, susceptible parent, resistant F2 bulk and susceptible F2 bulk in experiment VI. Bulked segregant analysis with the SSR primer CLM0008 revealed a polymorphic band at ≈ 300 bp which was appeared in the resistant parent and bulk. Bulked segregant analysis with ISSR primer UBC 811 produced polymorphic bands at ≈ 1100 bp, which were present in resistant parent and resistant bulks. The identified markers linked with resistance were validated over the resistant F2 lines obtained.ThesisItem Open Access Breeding hotset indeterminate tomato (Solanumlycopersicum L.) resistant to bacterial wilt suitable for protected cultivation(Department of Vegetable Science, College of Agriculture, Vellanikkara, 2021) Archana, K A; KAU; Pradeep Kumar, TThe present investigation was undertaken to develop an indeterminate hotset tomato with bacterial wilt resistance through line × tester analysis. The experiment was conducted at the Department of Vegetable Science, College of Agriculture, Vellanikkara, Kerala Agricultural University, during the year 2018- 2020. The first experiment was the performance evaluation of 35 tomato genotypes for two seasons in the year 2018, summer evaluation from January 2018 and rainy season evaluation from July 2018, in two protected structures viz., polyhouse and rainshelter. Genotypes exhibited significant variation for vegetative, flowering, fruit, yield and biochemical traits under both growing structures across season. Under polyhouse during summer the genotypes EC- 164263, EC-620387, EC-620401, EC-620406, EC-620410, and EC-620417 performed better for hotset traits (flowers with exerted stigma, pollen viability and fruit set per cent) and yield traits (average fruit weight, number of fruits per plant and yield). In rainshelter, the genotypes EC-165395, EC-165690, EC- 538153, EC-620401, EC-620406, EC-620410 were superior. During rainy season, EC-164263, EC-538153, EC-620401, EC-620406, EC-620410, EC-631369 were superior under polyhouse, and EC-620395, EC-620401, EC-620406, EC-620410, EC-631369 and EC-631379 inside rainshelter, for hotset traits and yield traits. The pooled data of flowers with exerted stigma, pollen viability, fruit set per cent, number of fruits per cluster, days to first fruit set, average fruit weight, pericarp thickness, number of fruits per plant and yield per plant were subjected to multivariate analysis for discrimination of genotypes into clusters. Under polyhouse seven clusters and inside rainshelter five clusters were observed. The selection index was also applied for ranking of genotypes based on the hotset distinctions and yield attributes. The hotset genotypes with high yield potential, identified suitable for protected cultivation were EC-164263, EC-538153, EC- 620387, EC-620389, EC-620401, EC-620406, EC-620410, EC-620417 and EC-631369. The genotypes EC-620401 (1), EC-620406 (2) and EC-620410 (3) were selected as hotset line for the line × tester analysis. In the second experiment the genotypes were tested for bacterial wilt resistance. The 35 tomato genotypes were sown in 98 well pro-trays holding sterilised soil medium. Another set of pro-trays holding the same medium were drenched with bacterial suspension with OD adjusted 0.8 to 1.3 at 600 nm and kept as the sick pro-trays. The twenty-one days old seedlings were used for inoculation through root dip method. With the help of sterilized scissors the tertiary roots of the seedlings were sectioned. The root clipped seedlings were dipped in bacterial suspension for thirty minutes. The inoculated seedlings were transplanted in the sick pro-trays. The entire experiment was conducted inside rainshelter with three replications. Each replication had five plants per genotype. Periodical observation on bacterial wilt symptom expression was taken from third day onwards. The disease index has revealed EC-620382 (0.20) and Arka Abha (0.20) as highly resistant. Nine genotypes viz: EC-165395 (0.24), EC-165700 (0.25), EC-521067 B (0.25), EC-620376 (0.30), EC-620378 (0.28), EC-620427 (0.21), EC-620429 (0.23), Akshay (0.21), Anagha (0.28) were resistant. From these EC-620382 (4), EC-620427 (5), EC-620429 (6) and Arka Abha (7) were selected as testers. In the third experiment, the identified lines and testers were crossed and seeds were collected for twelve cross combinations. The fourth experiment was the evaluation of F 1 hybrids from third experiment during summer in two protected structures viz., polyhouse and rainshelter. The cross combinations were laid along with the parents and two checks viz., one check hybrid (Abhilash) and one check variety (Akshaya). The mean performance, relative heterosis (RH), heterobeltosis (HB), standard heterosis (SH) and combining ability studies were conducted. For vegetative traits, the cross combination 3 × 7 exhibited superiority in the mean performance with significant positive sca effects in both the structures. For flowering traits, the cross 2 × 5 exhibited significant positive sca effects for pollen viability and significant negative sca effects for flowers withexerted stigma with significant RH, HB and SH in both the structures. In the case of fruit and yield traits, the cross combination 2 × 5 exhibited negative significant sca effects for days to first fruit set and positive significant sca effects for pericarp thickness, average fruit weight and yield per plant with significant RH, HB and SH. Inside rainshelter, 3 × 5 and 3 × 7 noted significant sca effects and positive significant heterosis for fruit and yield traits. For biochemical traits, the cross combination 2 × 5 exhibited positive significant sca effects and positive significant RH, HB and SH for TSS, ascorbic acid and acidity under polyhouse. In the seedling stage, all cross combinations exhibited resistance reaction to bacterial wilt in the challenge inoculation. Depending on the mean performance, heterosis and sca effects, the cross combination 2 × 5 was recommended for polyhouse and the crosses 3 × 5 and 3 × 7 were recommended for rainshelter. None of the parents revealed significant and desirable gca effect for all traits studied. The comprehensive assessment of the parents by considering gca estimates revealed that among lines EC-620406 is a good general combiner for vegetative, fruit and yield characters under polyhouse, and EC-620406 and EC- 620410 could be regarded as good general combiners for vegetative, reproductive, fruit and yield, quality characters and shelf life inside rainshelter. In the case of testers EC-620427 and Arka Abha were good combiners for vegetative, reproductive, fruit characters and shelf life in both the growing structures. Dominant gene action was observed predominantly for characters studied under both the structures. Plant height at harvest, days to 50% flowering, days to first fruit set, days to first fruit harvest, number of fruits per plant, average fruit weight, yield per plant, yield per plot, lycopene, ascorbic acid, shelf life, flowers with exerted stigma, pollen viability, number of flowers per cluster, number of fruits per cluster and fruit set per cent exhibited dominant gene action under both the structures. Pericarp thickness exhibited complete dominance inside rainshelter.In the fifth experiment, available SSR markers were validated for bacterial wilt resistance. Two SSR markers, SLM6124 and SLM6-110, produced polymorphism between resistant and susceptible genotypes, two distinct bands for resistant genotypes and four bands (two distinct and two fainted) for susceptible genotypes. In conclusion, the work indicates the change in the behaviour of genotypes under different protected structures in different seasons. Hence the selection of genotype and structure depending on the season is important. The heterosis breeding is effective in improving hotset traits in tomato. The hybridisation involving one resistant parent can generate bacterial wilt resistant off-springs. The application of molecular markers can effectively reduce the time and labour intensive field evaluation.ThesisItem Open Access Breeding for resistance to fruit fly (Zeugodacus spp.) in oriental pickling melon (Cucumis melo(L.)var.conomon Mak.)(Department of vegetable science,College of Horticulture, Vellanikkara, 2020) Silpa, Ramachandran.; KAU; Anitha, P“Breeding for resistance to fruit fly (Zeugodacus spp.) in oriental pickling melon (Cucumis melo (L.) var. conomon Mak.) ABSTRACT Melon fruit fly (Zeugodacus spp.) is one of the major pests in cucurbits and it causes a loss of 32-100 per cent depending upon seasons and prevailing climatic conditions. The developing resistant varieties either by selection from germplasm lines or through backcross breeding is an economical way to reduce fruit loss in oriental pickling melon. Keeping this in view, the present investigations entitled “Breeding for resistance to fruit fly (Zeugodacus spp.) in oriental pickling melon (Cucumis melo (L.) var. conomon. Mak.)” was undertaken to identify sources of resistance to fruit fly infestation form germplasm; to incorporate fruit fly resistance into high yielding genotypes and to study the genetics of inheritance. Two separate experiments were designed for the study. Fifty three oriental pickling melon accessions were catalogued as per Minimal Descriptor of Vegetable Crops- Cucumis melo (L.)- NBPGR (2000). High variability was observed for all the morphological traits except flower colour. Oblate followed by globular and elongate were the predominant fruit shapes. White, creamy white, white with orange shade were observed for flesh colour. Fruit taste was sour, sweet; none of the accessions had bitterness. The traits viz., node of first female flower, vine length, number of seeds per fruit, number of fruits per plant, days to last harvest and percentage of fruit fly infestation exhibited high GCV, PCV, heritability and GA which indicated that these traits were highly heritable and could be improved through selection. Yield per plant was positively, significantly correlated with number of branches per plant, fruit diameter, fruit girth, fruit length, fruit weight, seed cavity length, seed cavity breadth and number of fruits per plant. High heritability was exhibited by all these traits. Therefore, simultaneous selection for these traits would improve yield. Significant negative correlations to fruit fly infestation were observed for traits viz., fruit diameter, fruit rind thickness, flesh thickness, marketable yield per plant, days to fruit fly infestation after anthesis. These traits exhibited high heritability hence, direct selection of higher mean values would improve yield and fruit fly resistance. Mahalanobis D2 analysis grouped the 53 accessions into 8 clusters. Cluster I had maximum number of accessions (12) followed by cluster II (9). The maximum inter cluster D2 value was between cluster VI and cluster V. Cluster mean for yield contributing traits were high in cluster V which consisted the promising accessions viz., CM022, CM045, CM047 and CM051. Cluster mean for fruit fly resistance contributing traits were high in cluster IV and cluster VI, where the promising accessions with respect to fruit fly resistance viz., CM012, CM033, CM034 and CM056were distributed. Two species of fruit fly were identified viz., Zeugodacus cucurbitae and Zeugodacus tau during the crop seasons. Hybridization was undertaken to incorporate fruit fly resistance into high yielding accessions from wild as well as resistant genotypes. Accessions viz., CM022, CM033, CM045, CM047, CM051, CM060, CM061 and CM062 selected as female parents; fruit fly resistant genotypes (Cucumis melo var. agrestis (W-10), Cucumis melo var. agrestis (W-51), Cucumis melo ssp. callosus and CM033) were selected as male parents. Thirty one F1’s were evaluated for morphological characters and resistance to fruit fly. High variability was observed for all the morphological traits except flower colour. Oblate followed by elliptical and elongate were the predominant fruit shapes. White, creamy white, white with orange shade were observed for flesh colour. Fruit taste was sour, sweet and bitter. Based on yield, quality, absence of bitterness and resistance to fruit fly, four F1’s were selected viz., CM045 x CM033(3.04kg) (Cross I), CM061 x CM033 (3.26kg) (Cross II), CM051 x Cucumis melo ssp. callosus (2.34kg) (Cross III), CM033 x Cucumis melo ssp. callosus (1.96kg)(Cross IV) for generation mean analysis. Generation mean analysis revealed that earliness traits were predominantly determined by dominance (h) gene effects coupled with duplicate epistasis. Hence improvement of earliness in flowering, fruiting and harvesting may be achieved by heterosis breeding. Yield contributing traits were governed by additive x additive (i), additive x dominance (j) and dominance x dominance (l) coupled with duplicate epistasis which indicated that hybridization followed by selection is appropriate. Fruit fly resistance traits were largely determined by additive x additive (i), additive x dominance (j) and dominance x dominance (l) effects coupled with duplicate epistasis. Selection and or hybridization followed by selection can be used. Number of fruits per plant, fruit rind thickness (Cross I), fruit girth (Cross II), fruit diameter (Cross II & III), day to last harvest (Cross III) exhibited complementary epistasis with significant additive (d), additive x dominance (j) and dominance x dominance (l) gene effects revealed that selection from segregating population could improve these traits. Correlations of biochemical traits of six generations to fruit fly infestation revealed that lower content of total soluble solids, total soluble sugars, total sugars; higher content of crude protein, total phenols, silica and tannins favoured resistance to fruit fly infestation. Evaluation of sensory qualities of fresh, cooked fruits of six generations in four crosses revealed that highest overall acceptability for fresh, cooked fruits was in CM045 (P1) Cross I and CM061 (P1) CrossII. The present investigations revealed that high variability was observed for all the morphological traits and resistance to fruit fly in oriental pickling melon accessions. Two species of fruit fly viz., Zeugodacus cucurbitae and Zeugodacus tau were identified during the crop seasons which infested different accessions. High heritability was observed for yield and fruit fly resistance. Fruit diameter, fruit rind thickness and flesh thickness exhibited high heritability, significant positive correlations with yield and significant negative correlations with fruit fly infestation. Simultaneous selection based on these traits would improve yield as well as fruit fly resistance. High magnitude of fruit rind thickness, flesh thickness and days to fruit fly infestation after anthesis along with hairiness on stem and fruit contributed to fruit fly resistance. High crude protein, total phenols, tannins and silica content of fruits contributed resistance to fruit fly whereas, high sugars, total sugars, total soluble solids favored fruit fly infestation. Generation mean analysis revealed that selection from segregating generations, heterosis breeding would be appropriate to improve yield along with fruit fly resistance.
