Sood, V.K.Singh, Sanjeet2019-01-302019-01-302018-05-26http://krishikosh.egranth.ac.in/handle/1/5810092904The present investigation entitled “Studies on gene action for agro-morphological traits and factors affecting haploid production efficiency following chromosomal elimination technique in oat (Avena sativa L.)” was carried out at the Forage Section and Experimental Farm of the Department of Crop Improvement, CSK HPKV, Palampur to gather information on genetic architecture for forage yield and component traits and to generate euhaploid embryos following wide hybridization in oat. The experimental material comprised of 45 triple test-cross progenies derived by mating 15 lines and three testers viz., PLP 1(L1), HJ 8 (L2) and their F1 (L3) for gene action studies and eight genotypes for wide hybridisation in an attempt to obtain haploid embryos. The genetic material was evaluated for 13 agro-morphological traits in a randomised complete block design with three replications during rabi 2016-17. Sufficient variability was observed in the TTC progenies for all the traits studied. Epistasis was found to be integral part of genetic variation for all the traits. „i‟ type epistatic interaction estimates were significant for seven traits and „j+l‟ type interaction was significant for all the traits, although the magnitude of „i‟ type interaction was higher for days to 50% flowering, days to 75% maturity, plant height and protein content. Both additive and dominant components were significant for all the traits except for protein content, with additive component being more pronounced indicating the relative importance of fixable type of gene action in their inheritance. Comparison of the D and H components revealed that both were underestimated in line × tester approach, with the underestimation being comparatively more with respect to additive genetic variance (-99.31% to -100%) to dominance genetic variance (-72.19% to -96.39%). Combining ability estimates showed significant genetic variance in lines for all traits whereas testers had significant genetic variance for six traits. Lines RO 19, IG 03 205 and EC 528865 were overall good general combiner for most of the traits and potential parent sources for recombination breeding. SCA estimates showed cross-combinations viz., HFO 114 × PLP 1 (A × A), HFO 114 × HJ 8 (A × A), OS 6 × PLP 1 (P × G) and JPO 46 × HJ 8 (G × P) having highest values for green fodder yield per plant, harvest index and seed yield per plant. HFO 114 × HJ 8 (G × G) showed highest estimates for both SCA and standard heterosis for seed yield per plant, green fodder yield per plant and harvest index and IG 03 205 × PLP 1 (G × G) for protein content. For haploidy induction the natural temperature and photoperiod regime were found to be non-conducive for induction of haploid embryos in this experiment. Direct application of phytohormone combination of 2,4-D + GA3 with concentrations of 50 ppm each to the pistil of the top five florets gave highest percentage of caryopsis. The genotype of the pollen parent and the seed parent did not have any significant impact on the caryopsis development.ennullThesis