Paul, SatishKUMAR, NIMIT2017-05-292017-05-292016-11http://krishikosh.egranth.ac.in/handle/1/5810012892ABSTRACT The research endeavour entitled ―Molecular characterization of rust resistance introgressed into Linum usitatissimum L. from its wild and cultivated gene pool‖ was executed in the Department of Crop Improvement, CSK HPKV, Palampur and Agricultural Research and Extension Centre (SAREC), Kangra during the years 2012-13 to 2016-17 with the objective to evaluate the crossability of different wild species with its cultivated species, transfer resistance against linseed rust, study the genetics of rust resistant gene(s), identify molecular markers linked to rust resistance gene(s) and nature and magnitude of gene effects for yield and its component traits. The experimental material comprised of six cultivated varieties of L. usitatissimum L. namely T-397, Chambal, Kangra Local, HimAlsi-1, Nagarkot & HimAlsi-2 and two wild species viz., L. angustifolium & L. grandiflorum. Interspecific hybridization revealed that L. angustifolium is crossable with cultivated varieties and has shown maximum crossability of 78.00 and 79.13 percent during 2012-13 and 2013-14, respectively at the temperature range of 10.00 to 24.70°C. The highest seed formation efficiency was observed in cross HimAlsi-2 x L. angustifolium (52.00 and 49.05 percent during 2012-13 and 2013-14 respectively ) at the temperature range of 5.91-22.43°C. The interspecific and intervarietal hybrids developed involving T-397 x L. angustifolium and T-397 x HimAlsi-1, were true to type based on confirmation at the morphological and molecular level. Inheritance of rust under natural epiphytotic conditions in T-397 x L. angustifolium and T-397 x HimAlsi-1 indicated the involvement of single dominant gene for disease resistance. Linkage analysis of the F2 mapping population revealed that the forward marker locus OPA 18 and reverse locus JA23 and rust resistance gene are located 5.8cM and 3.4cM apart, respectively for T-397 x L. angustifolium, whereas, in case of T-397 x HimAlsi-1 it was 1.9cM (OPA 18) and 3.3cM (JA 23) apart from the rust resistance gene. Further, evaluation of crosses using line × tester analysis in a randomized complete block design with three replications revealed highly significant differences among the genotypes for all the characters studied. Both dominance and additive genetic variances were important for the traits but dominance was predominant as compared to additive variance. Line Chambal and tester HimAlsi-1 showed good general combining ability for eight characters. The cross combinations, T-397 x Nagarkot, HimAlsi- 2 x HimAlsi-1, HimAlsi-2 x L. angustifolium, T-397 x HimAlsi-1 and Chambal x Nagarkot showed high, SCA effects, heterobeltiosis and economic heterosis for seed yield per plant and were rated as potential crosses for further improvement.ennullThesis