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Open Access
Characterization and QTL mapping of Teosinte derived maize population for BLSB resistance and other traits
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Adhikari, Sneha; Singh, N.K.
The investigation was carried out with the aim to map genomic region for resistance to banded leaf and sheath blight and other traits. The field experiments were conducted during rabi 2016-2017, kharif 2017, rabi 2017-18 for development of mapping population while kharif 2018 season was used for phenotyping of BC1F5 mapping population under artificially inoculated with Rhizoctonia solani and control conditions. Among BC1F3 and BC1F4 generation of teosinte derived maize population, large phenotypic variation was observed for all morphological traits, hence teosinte can be used for enhancing maize germplasm. Of the 126 lines 76, 20 and 21 lines were of protogynous behaviour, short ASI (0-1 days) and bears > 3 ears per plant, respectively in both BC1F3 and BC1F4 generations. Jaccard similarity coefficients and dendrogram generated using SSR markers data indicate 25 percent genetic similarity in maize and teosinte. Analysis of variance showed highly significant variation among the BC1F5 lines for disease reactions and other traits. Among 169 BC1F5 lines, 9 (MT-25, MT-90, MT-99, MT-128, MT-136, MT-144, MT-145, MT-148, MT-152) comes under the category of moderately resistant class and can be utilize in maize BLSB resistance breeding. Analysis of variance (ANOVA) revealed significant variance between the environment for days to anthesis and silking, anthesis-silking interval (ASI), flag leaf length, flag leaf width, ear per plant, ear length, ear diameter, kernel rows per ear, kernels per row, test weight and grain yield per plant. It indicates greater impact of disease stress on these characters. Correlation analysis exhibited significant correlation of BLSB resistance with flag leaf angle, plant height, ear length, ear diameter, kernel rows per ear, kernels per row, test weight and grain yield per plant. The single-marker ANOVA revealed a total 125 QTLs, of these 4 were major and 121 were minor QTLs for 14 traits. These QTLs were distributed over 10 chromosomes with phenotypic variation ranges from 2.29 to 12.98 per cent. Out of 125 QTLs, 64 and 61 QTLs were detected in E1 and E2, respectively and of which 20 QTLs were common in both the environments. Maximum QTLs were detected in chromosomes 4 and 9 followed by 7, 6, 10, 5, 2, 1, 3 and 8. Consistent QTLs across the environments were identified for days to anthesis (3), days to silking (2), flag leaf length (1), flag leaf width (1), plant height (2), ears per plant (1), node bearing first ear (2), ear length (2), ear diameter (1), kernel rows per ear (3), test weight (1) and grain yield per plant (1). The single-marker ANOVA analysis revealed one major QTL on chromosome 5 and four minor on chromosomes 1, 3, 4 and 8 for BLSB resistance under DE1. In DE2 however only four minor QTLs one each on chromosomes 1, 3, 5 and 8 were identified. Out of these nine QTLs two were identified across the environments that were linked with markers umc1500 and phi10918, considered as stable QTLs. Among seven identified QTLs for BLSB resistance, a major QTL linked with phi10918 was colocalized with three minor QTLs for ear length, kernel rows per ear and kernels per row. Seven minor QTLs for days to anthesis, days to silking, ear length, ear diameter, kernel rows per ear, kernels per row and grain yield per plant were co-localized with a minor QTL for BLSB resistance that linked with marker umc1720. One minor QTL for BLSB resistance that was linked with phi420701 was collocated with a major QTL for plant height. Remaining two minor QTLs for BLSB resistance namely, umc1500-linked QTL and umc2000-linked QTL were colocalized with QTL for test weight and ear per plant, respectively. The investigation successfully identified lines with desirable traits that can be utilized in stress resistance breeding. Co-localized QTLs identified for various morphological traits and disease resistance can integrate/pyramid in breeding materials for improving BLSB resistance.
Open Access
Evaluation of red rot resistance potential of selected clones from segregating progenies of sugarcane (Saccharum Sp. Complex)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Tabassum; Jeena, A.S.
The present investigation entitled “Evaluation of red rot resistance potential of selected clones from segregating progenies of sugarcane (Saccharum sp. Complex)” was conducted with 142 bi-parental and general collection progenies along with five check and two parental varieties to investigate red rot resistance potential, estimation of genetic parameters, correlation and path coefficient, assessment of genetic diversity among clones and revalidation of 56 red rot related SSR markers to aid breeding programmes. The experiment wasconducted in augmented block design- II for two seasons during 2017 to 2019 at N.E.B. Crop Research Centre, G.B.P.U.A.&T.Pantnagar. Analysis of variance revealed that all the genotypes differed significantly for all the thirteen cane yield and juice quality characters under study. Based on mean performance, clone PC-2013-14-175 was identified as best performer for juice quality characters and PC-2013-14-221 for cane yield contributing characters. High magnitude of GCV, PCV along with high h2b and GAM were recorded for germination percent, number of tillers, NMC, cane yield and CCS yield indicatingthe prevalence of additive gene action in the expression of these characters. Correlation coefficient study revealed that cane yield exhibited highly significant positive correlation with seven characters viz., germination %, number of tillers, NMC, single cane weight, cane height, cane diameters and CCS yield at both phenotypic and genotypic levels. Path coefficient analysis revealed that CCS yield, sucrose percent and number of millable canes exerted higher positive direct effects on cane yield. CCS yield exerted higher positive indirect effects on cane yield via all the characters under study except through brix percent. The clones were clustered into 18 clusters through Mahalanobis D2 analysis. PC-2013-14-376 (cluster XIII), PC-2013-14-146 (cluster VII) and PC-2013-14-180 (cluster XVII) were identified as most promising clone based on their cluster means for cane yield and juice quality characters and these clones could be used as donors for future breeding programme. Marker trait association study based on eighteen polymorphic SSR markers revealed that Six markersviz., SMC278CS, RGA129, RGA057, SMs045, RGA281 and RGA152 were found to be tightly associated with red rot resistance by showing presence of bands in resistant clones but absence in susceptible clones. The significant association provides their worth for future use of these markers in marker-assisted selection for red rot resistance in sugarcane.
Open Access
Genetic studies on bacterial leaf blight resistance, variance, combining ability, heritability, heterosis and generation mean analysis in rice (Oryza sativa L.)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-05) Kushwaha, Ujjawal Kumar Singh; Indra Deo
This research included four experiments, genetic studies on bacterial leaf blight resistance, variance study of exotic rice genotypes, estimation of genetic parameters viz. combining ability, heritability, heterosis, and study of gene action through generation mean in rice. To understand the genetics of bacterial leaf blight resistance, F2 population derived from Pant Basmati 2 × BBL-180-5-1-4-1 was screened for bacterial blight reaction after artificial inoculation of Xanthomonas oryzae pv. oryzae at phenotypic level. For molecular study, about 1-2 gram leaf samples were taken from each F2 plants and used for DNA extraction. Only six primers RM13, RM21, RM164, RM206, RM224, and RM230 showed polymorphism during electrophoresis out of 15 simple sequence repeats used. Chi-square tests were found non significant indicating the observed and expected value were the same. The F2 plants segregated by 3:1 at phenotypic and 1:2:1 at genotypic level following Mendelian law of inheritance. Only 11 plants were resistant, 34 moderate resistant, 9 moderate susceptible and 13 susceptible both at phenotypic and genotypic level. Gene linked primers detected Xa4, Xa5, Xa10, Xa13, and Xa21 BLB resistant genes in F2 resistant plants which could be used to develop resistant variety. To characterize and compare rice yields and its attributing traits, two-season trials were conducted in a randomized complete block design with a standard check Pant Dhan 4 in 2016 and 2017. The tested genotypes were statistically significant (p<0.05) based on days to flowering and maturity, effective tillers, panicle length, fertile and sterile grains per panicle and yield. The average grain yield of all genotypes transplanted in 2016 (10, 153.85 kg/ha) was higher than 2017 (5, 598.38 kg/ha). A rise in minimum temperature of 3.41 0C was noticed during the grain filling period in 2017 than 2016 and predicted that the elevated night temperature was detrimental to rice productivity. The yield increment in 2016 might be due to favorable weathers and ideal night temperature during crop growth and development phase. Only four genotypes viz. IRRI 146, TP 29651, TP 29632 and IRRI 104 were found resistant to blight during both the years of experiments. Similarly, combining ability, heritability, heterosis and five generation mean were estimated by taking three susceptible and resistant varieties Pant Basmati-1, Pant Basmati-2, and Pant Sugandh Dhan 17 as lines and BBL-180-5-1-4-1, Oryza perennis and Improved Pusa Basmati 1 as testers to get P1, P2, F1, F2, and F3 populations from 2016 to 2018. Result showed maximum variations among the genotypes and their traits. The gca and sca values for different traits revealed the presence of additive and non additive gene interactions. The gca value suggested that Pant Basmati 1 was best line and BBL-180-5-1- 4-1 was best tester respectively. Pant Basmati 1 × Oryza perennis was best cross based on sca value. Pant Basmati 2 × Oryza perennis showed maximum heterosis followed by Pant Basmati 2 × BBL-180-5-1-4-1. Similarly Pant Basmati 1 × Pant Basmati 2 was considered best cross based on mid and better parents value. Heritability was at top for 100 grain weight in all crosses. Five generation mean analysis showed epistatic non allelic gene interactions like dominance, additive × dominance and dominance × dominance gene interactions.
Open Access
Studies on seed invigoration and effect of silica nanoparticles (SiO2) on seed quality parameters of maize (Zea mays L.)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Chourasia, Vinay Kumar; Shukla, P.S.
Open Access
Combining ability analysis for yield and quality parameter in sugarcane (Saccharum sp. Complex)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-01) Pandey, Deepanker; Singh, S.P.
Sugarcane is a major crop of tropical and sub-tropical regions worldwide and belongs to the family Gramineae , tribe Andropogoneae, sub tribe Saccaharinineae, genus Saccharum. Sugarcane varieties are complex poly-ploids and their chromosome number varies from 2n = 100 to 120 or more. The yield and quality components in sugarcane are quantitative in nature and governed by poly genes, which are largely influenced by environmental factors. Therefore, it is essential to judge what proportion of observed variation of a particular character is heritable or due to environmental variation along with the transmissibility of the character. The knowledge of combining ability (ability of a genotype to transmit superior performance to its crosses) together with per se performance of the parents and hybrids, and heterotic response helps the breeders in selecting suitable parents and crosses for their use in a systematic breeding programme. Several techniques are available to elucidate the genetic makeup of the parents with respect to their ability to transmit characters of interest. Among those, the present study utilized Line × Tester and NC-I mating design to evaluate the genetic potential of parents based on the General Combining Ability estimates for different characters in Sugarcane. The crosses were attempted at National Hybridization Garden at Sugarcane Breeding Institute; Coimbatore Tamil Nadu for both Line × tester design and NCD-I mating and later on evaluation of progenies were carried out at the Sugarcane Breeding Experimental Block of Norman Borlaug Crop Research Centre, GBPUA&T, Pantnagar, U. S. Nagar, Uttarakhand during 2013-2017. The observations were recorded for eight morphological and five quality traits and analyzed through standard statistical procedures of the mating designs. General combining ability analysis from Line × Tester design revealed that Co Pant 99213 was a good general combiner for germination percent, number of tillers and number of millable canes, while Co Pant 94213 found good combiner for Brixpercent, pol value, sucrose percent and C.C.S. percent. Tester, Co Pant 97222 had good general combining ability for germination percent and number of tillers. Results of North Carolina Design Irevealed that Co 775 exhibited positive significant gca values for Cane Height, Pol value, Sucrose percent and C.C.S. Percent, which is sufficient to conclude that this is gooddonor for these traits. Highheritability accompanied by higher genetic advance under selection was found in case of Germination Percent, number of tiller, NMC(000/ha), and Pol value, reflecting predominance of additive genetic effect for these traits. These traits could be used as indices for selection under Sugarcane improvement programme. Results of heterosis analysis concluded with the identification of two best hybrids namely Co Pant 84212 × Co Pant 97222 and Co Pant 99213 × Co Pant 97222 which can be promoted through vegetative propagation for yield trials. As the F1 progenies in Sugarcane offers segregation and transgressive recombinant, the best clones with high sugar and early maturing sugarcane can be selected from the progenies of these crosses for identification of superior clones to develop improved sugarcane varieties.
Open Access
Early generation selection based on genetic parameters and molecular diversity in parental lines of soybean [Glycine max (L.) Merrill]
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-01) Bisht, Meenakshi; Singh, Kamendra
The present investigation was carried out with the objectives to study the efficiency of early generation selection, residual heterosis, transgressive segregation, inter-character association and their direct and indirect effects on yield and molecular marker analysis using seventeen different SSR primers for effective selection of genotypes and improvement of soybean. For field experiment, 36 genotypes of soybean comprising 14 crosses, 20 parents and two checks (PS 19 and SL 688) were evaluated in F2 generation using randomized block design with two replications in kharif 2015 and 14 crosses along with their 21 progenies (10 high value group, 10 low value group and 10 bulk) were evaluated in compact family block design with two replications in kharif 2016 at the Norman E Borlaug Crop Research Centre, G.B. Pant University of Agriculture and Technology, Pantnagar. The Analysis of variance was found highly significant for all the characters undertaken in both the generations. The study on early generation selection with various genetic parameters revealed that characters days to 50% flowering, plant height, number of pods per plant and seed yield per plant exhibited positive and significant value for intergeneration correlation coefficient. The estimate of intergeneration regression coefficient revealed that days to 50% flowering, plant height and seed yield per plant were positive and significant. The number of pods per plant and seed yield per plant displayed significant and positive value for response to selection. High heritability coupled with high genetic advance was observed for seed yield per plant in both the generations. The value of realized heritability was found higher for days to 50% flowering, number of pods per plant and seed yield per plant. High performance of F3 bulk than F2 generation and F3 high group proved bulk method to be more effective than the pedigree method The per se performance of F2 generation for seed yield per plant was highest for three crosses, PS 1584 X JS 20-69 (20.7g), PS 1583 X JS 20-29 (20.08g) and PS 1225 X PS 1347 (19.58 g), for F3 high yielding group it was highest in PS 1584 X JS 20-69 (42.63g), PS 1583 X JS 20-29 (33.40g) and PS 1584 X JS 20-41 (29.79g), similarly the per se performance in F3 bulk was highest in PS 1584 X JS 20-69 (50.12g), JS 20-29 X JS 20-55 (39.76g) and JS 20-69 X JS 20-59 (35.63g). On overall basis, seed yield per plant was found to be effective for early generation selection. The study of nature and magnitude of residual heterosis revealed that PS 1584 X JS 20-41. PS 1583 X Bragg, PS 1584 X JS 20-69 and PS 1583 X JS 20-29 showed significant and positive residual heterosis over mid-parents. Over better parent, PS 1584 X JS 20-41 and PS 1583 X Bragg showed significant and positive residual heterosis over better parent, while PS 1584 X JS 20-69 showed positive and significant residual heterosis over both the checks, in F3 generation while none of the crosses showed significant residual heterosis in F2 generation. All the F2 crosses showed positive transgressive segregants for seed yield per plant but moderate frequency was observed. Highest positive transgressive segregant for seed yield per plant was recorded in the cross, PS 1042 X PS 1347. Occurrence of transgressive segregants in segregating generation is helpful for development of homozygous lines by continued selfing in crops like soybean. The present study revealed that in F2 and F3, dry matter weight per plant, plant height, number of primary branches per plant, number of pods per plant, number of seeds per pod and harvest index exhibited significant and positive correlation with seed yield per plant. The component characters which showed highest direct effect on seed yield per plant were harvest index and dry matter weight per plant in F2 generation and number of pods per plant in F3 generation indicating selection of these characters will bring direct improvement in seed yield The molecular diversity analysis of twenty two soybean genotypes revealed that the Jaccard’s similarity coefficient estimates varied from 0.29 (JS 20-59 and Pb1, JS 20-54 and Pb1, PS 1584 and PS 1347, JS 20-41 and PS 1347) to 0.82 (JS 97-52 and JS 20-29, PS 1583 and RVS 200-1, PS 1583 and JS 20-29 and PS 1042 and Pb1) genetic similarity. The average number of alleles per marker was 1.88, while percentage of all bands showed the polymorphism was 100%. The dendrogram constructed from SSR marker data divided twenty two genotypes into two main groups A and group B which consisted of seven clusters: Cluster I, II, III, IV, V, VI and VII. On the basis of dendrogram, genotypes PS 1225 and JS 20-59 was found to be most distant.
Open Access
Mapping drought tolerance using teosinte derived BC1F2 population of maize (Zea mays L.)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Amarjeet Kumar; Singh, N.K.
The present investigation was undertaken with wild progenitor teosinte (Z. mays ssp. parviglumis) and a maize inbred line DI-103.The 203 lines of BC1F2 mapping populations were phenotyped in two environmental conditions i.e. irrigated and moisture stress condition during the rabi season 2016-17 for twenty five morpho-physiological traits associated with drought tolerance. Phenotyped data were subjected to single marker analysis using forty three polymorphic markers. A total of 82 QTLs were identified to be associated with twenty four morpho-physiological traits except leaf firing. Out of 82 QTLs, four QTLs were found major QTLs and they were associated with anthesis silking interval, leaf rolling, plant height and thousand kernels weight. One major QTL linked with marker phi113 was detected for anthesis silking interval accounted for 11.79 per cent phenotypic variation. Marker umc1303 was linked with the major QTL responsible for 14.67 per cent phenotypic variation for leaf rolling .Two other minor QTLs were linked with the marker umc1444 and umc1156 explained 3.84 and 2.28 per cent of phenotypic variation for leaf rolling. The major QTL linked with marker umc1171 accounted for 13.25 per cent phenotypic variation for 1000 kernel weight. For the identification of drought tolerant lines rank score was used. The basis of ranking was the least reduction or positive increase between the performance of genotype in irrigated and moisture stress condition. Thirteen morpho-physiological traits from total of twenty five traits associated with the drought tolerance were used for identification of drought tolerant lines. Overall sum of rank scores for thirteen traits associated with drought tolerance revealed that AM-39 was the most drought tolerant genotype among all the 203 lines studied with total score of one hundred eight, followed by AM-64, AM-16, AM-42, and AM-102, whereas, AM-116 was the most susceptible with the least score of thirty four. The molecular characterization of five teosinte derived lines BC1 F4 reflected that the maximum allelic contribution lines from parent teosinte (Z. mays ssp. parviglumis) was found in the introgressed line AM-5 (53.4 per cent) followed by AM-12 (48.9 per cent), whereas, least contribution of 34.1 per cent was found in AM-7.The maximum contribution of 53.4 per cent from parent DI-103 was found in introgressed line AM-7 followed by AM-2 (42 per cent) and the least contribution was exhibited by AM-5 (27.3 per cent) followed by 33 per cent in the AM-12.The morphological characterization of teosinte derived BC1F4 lines exhibited that the yield contributing traits namely number of cobs ranged from 2 to 5. The maximum number of cob was found in AM-5 (5.00) followed by AM-2 (4.00). The largest variation in parents among all morphological traits was found in number cobs per plant i.e. inbred DI-103 (1.80), whereas, teosinte had 417 cobs. Ear length varied from 8.00 cm (AM-7) to 13.50 cm (AM-5). It is therefore, present findings might be concluded that the different morpho-physiological character associated with drought tolerance in maize and could be useful to combat the drought tolerance along with domestication of wild alleles.
Open Access
Genetics of resistance and molecular analysis of botrytis grey mould in chickpea (Cicer arietinum L.)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Bhardwaj, Rajneesh; Panwar, R.K.
Chickpea (Cicer arietinum L.) is the second largest consumed pulse crop of the world after common bean and it is grown in over 50 countries and traded across 140 countries. The beneficial effects of chickpea on soil health and human health are well recognized. There has been a slow progress in improving the average global productivity of chickpea, which continued to remain below 1.0-ton ha-1. In India, chickpea was planted in 8.25 million hectares during 2016-17 with a production of 7.33 million tons and a productivity of 859 kg/ha. However, the breakthrough in its productivity is still awaited because of the number of biotic and abiotic stresses constrain productivity. Botrytis gray mould (BGM) caused by Botrytis cinerea is one of the major constraints for low yield of chickpea. This disease leads to subsequent crop loss in certain parts of India (in Tarai area of Uttarakhand, Tal area of Bihar and in Punjab). The present investigation was carried out in Rabi seasons during 2014-15, 2015-16 and 2016-17 at N. E. Borlaug Crop Research Centre and Pulse Breeding Laboratory of G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India with the objectives to study the genetics of resistance to botrytis grey mould (BGM) disease and molecular analysis of BGM disease in chickpea. The experimental material comprised of resistant parents viz., GL10006, DKG876 and susceptible parents viz., DCP92-3, GNG1581 and H 208. Screening for resistance to botrytis grey mould disease was done by using field screening technique which involves spraying artificial inoculums of a pathogen. Disease scoring was done using the 1-9 scale. Resistance was found dominant over susceptibility in the F1 generation of six resistant × susceptible crosses viz. GL10006×GNG1581, GL10006×DCP92-3, GL10006×H208, DKG876×GNG1581, DKG876×DCP92-3 and DKG876×H208. In the F2 generation, 3(resistant): 1(susceptible) ratio was found for all resistant × susceptible crosses indicating that resistance was governed by a single dominant gene. Backcross of F1 with resistant parents gave all resistant plants and backcross with susceptible parent gave segregants into 1(resistant): 1(susceptible) ratio. The crosses between resistant (GL10006) × resistant (DKG876) parents (test of allelism) suggested that the dominant resistance gene in both the parents were different as F2 generation of this cross showed segregation in15:1 ratio. In another experiment, STMS markers were tested for their association with botrytis grey mould resistance genes in parents, F1 and the F2 population of cross GL10006 (resistant parent) × H208 (susceptible parent) of chickpea. In preliminary studies, total 28 STMS was used out of which 13 primers viz., TA203, TA47, TA43, TS9, TAA137, ICCM068, ICCM0160, TA34, TS72, TA118, TS57, TA25 and TA144 were identified with polymorphic bands in the resistant and susceptible parent. These polymorphic primers were also screened in the F1 and F2 population. In F1 plants, amplified band size was similar to the resistant parent. Plants in F2 generation have amplified bands of either resistant or susceptible parents because in the F2 generation, plants were segregated into resistant and susceptible plants. To identify the putative marker-trait association, the genotypic and phenotypic data of cross between resistant parent (GL10006) and susceptible parent (H208) were subjected to single marker analysis. Results of single marker analysis indicated that five markers ICM0068, TS72, TA118, TA25 and TA144 were associated with BGM resistance. BGM resistance locus (QTL) associated with TA118 primer explained the most 28.25% of total phenotypic variation for BGM resistance. Whereas TA25, TA144, TS72, ICM0068 explained 0.05%, 5.5%, 7.85%, 0.39% of total phenotypic variation for BGM resistance, respectively. Polymorphic markers identified in the present study will be useful for identification of markers linked with BGM resistance which can further assist in marker-assisted selection for resistance breeding.
Open Access
Evaluation of drought tolerance potential in early generation progenies of sugarcane (Saccharum Sp. Complex)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Koujalagi, Deepak; Jeena, A.S.
The present investigation entitled “Evaluation of drought tolerance potential in early generation progenies of sugarcane (Saccharum Sp. Complex)” was conducted with 65 Bi-parental progenies along with parents and six check varieties viz., Co 0238, Co J 64 and Co Pant 03220 (early) and Co Pant 97222, Co Pant 05224, CoS 8436 (mid-late) to investigate drought tolerance potential based on physio-biochemical characters, studies on genetic parameters and revalidation of candidate gene specific molecular markers to aid breeding programme. The experiment was conducted in augmented block design- II in two seasons with two environments such as control at N.E.B.C.R.C. and stress at P. C.P.G.R. G.B.P.U.A&T, Pantnagar during spring 2017 and autumn 2017-18. The drought stress was created by withdrawing the irrigations during the 50 DAS to 200 DAS. The data was recorded on 16 physiological and biochemical characters for estimation of genetic parameters, genetic diversity analysis and selection indices. Further, Twenty five selected clones were utilized for candidate gene specific molecular markers validation study at Plant Biotechnology lab, Department of Genetics and Plant Breeding. Analysis of Variance (ANOVA) for four environments revealed that traits like proline content and leaf firing exhibited significant differences in stress unlike control environment indicating that these traits are of very high utility in selection for drought tolerance. The effect of water stress was clearly reflected by the reduced mean values for almost all the traits except an increase in proline content under stress. High PCV and GCV along with high heritability and high genetic advance as percent of mean was observed for CTD 60, CTD 120, CTD 180, Chl a, Chl b, Total chlorophyll, Total carotenoids Proline content, RWC % and Leaf firing indicating the prevalence of additive gene action in expression of these characters. Estimates of path coefficients revealed that Traits like Chl a, Chl b, total chlorophyll, SPAD 120, SPAD 180 and proline content were found to confer positive direct as well as indirect effects on DTC which supports their utilization as a reliable tool in selection for drought tolerance in sugarcane. Under both the environmental conditions highest inter-cluster distances were found to be between a drought tolerant cluster and a drought sensitive cluster. Cluster I, III and IV were found to comprise desirable clones for most of the traits. Germination percent, Chl a, RWC percent, leaf firing, total carotenoids, SPAD 60, Chl b, DTC and proline content contributed approximately 70 percent of the total divergence. Based on the selection scores the genotypes namely PC (2015-16)-55, PC (2015-16)-26, PC (2015-16)-40, PC (2015-16)-54, and PC (2015-16)-1 were found best ones among drought tolerant genotypes. Validation analysis of the marker trait association with respect to candidate gene specific markers and drought tolerance through t-test revealed that four markers DREB 1A, NAC 2, Snac 1 and LEA 3 recorded significant difference between the means of the two groups. The significant association proves their worth for future use of these markers in marker-assisted selection for drought tolerance in sugarcane.

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