Studies on combining ability gene action for seed yield and its component traits in urdbean Vigna mungo L Hepper

Abstract

The present investigation entitled Studies on combining abilitygene action for seed yield its component traits in urdbean (Vigna mungo (L.) Hepper) was undertaken to study the nature and magnitude of gene action for yield and its component traits and to identify potential parents that can be utilized in a breeding programme for high seed yield and early maturity. Nine urdbean genotypes were crossed in a half diallel, following Griffing s Method 2 and Model I. Experimental material comprising of nine parents, 36 F1 s and one check (Palampur-93) were evaluated in CRBD with three replications in kharif 2017 at Palampur. The combining ability analysis revealed significant GCA and SCA variances for all the traits except pod length, indicating that most of the traits were governed by both additive and non-additive gene action. The estimates of genetic components of variances as per Griffing s approach indicated partial dominance in seeds per pod and overdominance in all the other traits. DU-1 was good general combiner with respect to early flowering; Him Mash-1 and DKU-98 for early maturity; HPBU-111 and KU-553 for number of branches per plant and pods per plant; and DU-1 and KU-553 for seed yield. KU-553 was the most desirable parent as it exhibited significant GCA effect for most of the traits viz., branches per plant, pods per plant, pod length, biological yield, seed yield and crude protein. DKU-98 × IC-281994 was good specific combiner for maximum number of traits along with seed yield per plant. Significantly high SCA effects were observed in Palampur-93 × KU-553, Him Mash-1 × HPBU-124, HPBU-111 × KU-553 and DKU-98 × IC-413304 for earliness. Promising crosses with respect to seed yield and its component traits were HPBU-124 × HPBU-111, Palampur-93 × DU-1, HPBU-124 × DU-1, HPBU-111 × IC-281994, DU-1 × DKU-98 and DU-1 × IC-413304. newline Hayman s genetic component analysis revealed that majority of traits had significant additive and non-additive genetic variance with preponderance of later. The asymmetric distribution of positive and negative genes in parents was observed for most of the traits along with preponderance of dominant genes. Dominance appeared to be unidirectional in case of days to 75 per cent maturity, plant height, branches per plant, pods per plant, biological yield per plant, seed yield per plant and crude protein content and bi-directional in rest of the traits. One major gene group was found controlling each trait except days to 75 per cent maturity and branches per plant where, two major gene groups were involved. The assumptions of diallel were not fulfilled for plant height, pod length, harvest index and crude protein. Epistatic effects were influencing all the traits except days to 75 per cent maturity. These factors led to the disparity in the results observed from Griffing s and Hayman s approach. newline Two crosses viz., Him Mash-1 × HPBU-111 and HPBU-124 × IC-413304 exhibited high magnitude of heterobeltiosis for earliness. Heterobeltiosis and standard heterosis for pods per plant was exhibited by 17 and seven crosses respectively; and 18 and seven crosses, respectively, for seed yield. HPBU-124 × KU-553, HPBU-124 × IC-413304, HPBU-111 × KU-553, DU-1 × KU-553, DU-1 × DKU-98, DU-1 × IC-413304 and KU-553 × IC-413304 outperformed Palampur-93 for seed yield and can be further exploited to obtain high yielding transgressive segregants. Palampur-93 × HPBU-111, Him Mash-1 × HPBU-111 × HPBU-124 × DKU-98 and HPBU-111 × DKU-98 had moderate to high resistance reaction to anthracnose, Cercosporaleaf spots and powdery mildew under natural epiphytotic conditions at Palampur. HPBU-124 × DKU-98 also had high SCA effect and heterobeltiosis for seed yield per plant along with resistance to all the three diseases. Due to predominance of non-additive gene action, SSD or bulk pedigree method with selection in later generations will be the best breeding strategy to obtain maximum transgressive segregants. newline newline newline