Combining ability and heterosis for bud fly infestation and seed yield and it's attributes in linseed (Linum usitatissimum L.)
Abstract
Four bud fly-resistant germplasm lines viz., EC-1424, GS-234, IC-15888, and JRF-5 were crossed with three testers (Neelum, Neela, and Shekhar) in aline × tester mating design to develop 21 F₁ and 21 F₂ crosses. The study was undertaken to estimate combining ability and heterosis in linseed (Linum usitatissimum L.) for bud fly infestation, seed yield, and related traits. The analysis of variance for general combining ability (GCA) and specific combining ability (SCA) was highly significant in both F₁ and F₂ generations.
Based on per seperformance and GCA effects, the best general combiners identified in both F₁ and F₂ generations were Neela for days to flowering and bud length; IC-15888 for sepal thickness, maturity duration, and bud fly infestation at the dough stage; Shekhar and Neela for grains per capsule; Neela for test weight; GS-234 and Neelum for oil content. However, no common general combiner was found for bud width, capsules per plant, and seed yield per plant across both generations. For capsules per plant, Shekhar was a good combiner only in the F₁ generation.
Heterosis over the superior parent for bud fly infestation at the dough stage ranged from –99.03% (EC-1424 × JRF-5) to – 48.59% (Shekhar × Neelum) in the F₁ generation. Out of 21 crosses, 20 crosses exhibited significant negative economic heterosis for this trait. The top five promising crosses were EC-1424 × JRF-5, EC-1424 × Neela, GS-234 × IC-15888, GS-234 × JRF-5, and IC-15888 × Shekhar. Only one cross (EC-1424 × Shekhar) showed significant positive heterosis for bud fly infestation.
For seed yield per plant, heterosis over the economic parent ranged from 28.64% (JRF-5 × Neelum) to 51.90% (Shekhar × Neelum) in the F₁ generation. Among all crosses, six crosses exhibited significant positive heterosis. These cross combinations may serve as potential genetic resources in future linseed breeding programs aimed at improving yield and bud fly resistance.
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Introduction
Linseed (Linum usitatissimum L.), commonly known as "Alsi", belongs to the genus Linum of the family Linaceae and has a chromosome number of 2n = 30. Globally, linseed is an important oilseed crop cultivated over an area of 27.29 lakh hectares, with a total production of 25.2 lakh tons and an average productivity of 923 kg/ha. In India, linseed is cultivated over 3.226 lakh hectares with a total production of 1.525 lakh tons, registering a comparatively low productivity of 473 kg/ha. India ranks third in terms of area under linseed cultivation, after Canada and China, but stands fifth in production following Canada, China, USA, and Ethiopia (Anonymous, 2013).
Continuous efforts towards yield improvement through hybridization and the selection of suitable parents are essential components of crop improvement programs. The line × tester mating design provides an effective method for precisely estimating the combining ability of parental lines and identifying superior parents and cross combinations. In this context, the present investigation was carried out to study the nature of combining ability and the extent of heterosis for yield, its contributing traits, and oil content in linseed
Conclusion
Combining ability analysis was carried out in linseed during rabi 2020-21. The experimental material included in present study consisting 49 genotypes comprising 7 parents and 21 F and 21 F . The study revealed the importance of non-additive gene 1 2 action in the inheritance of all the traits and stresses the need for its exploitation either through heterosis breeding or suitable population improvement programme.
On the basis of per seperformance and gca effects good general combiners common in both F and F generations were Neela 1 2 for days to flowering and bud length, IC-15888, sepal thickness, maturity duration and Grain/capsules. Shekhar and Neela, for dough stage bud fly infestation %, Neela, for test weight GS-234 and Neelum and for oil content Shekher. The best five crosses are EC-1424× JRF-5, EC-1424× Neela, GS-234 × IC-15888, GS-234×JRF-5 and IC-15888×Shekhar. Only one cross showed positive significant (EC-1424× Shekhar). In seed yield per plant shows the heterosis over economic parent ranged from 28.64 (JRF-5×Neelum) to 51.90 (Shekhar×Neelum) inF generation. In all crosses, six cross as showed positive and significant 1 heterosis. These crosses combinations could be utilized for further use inbreeding programme for improvement in yield of linseed.
