Heterosis and Combining Ability in a Diallel Cross of Ethiopian Mustard Inbred Lines

Abstract

Becker et al., 1999;Miller, 1999). Studies in B. napus, B. rapa, and B. juncea have indicated high levelsHeterosis is commercially exploited in rapeseed (Brassica napus of heterosis. Pradhan et al. (1993) reported 29 to 92% L.) and its potential use has been demonstrated in turnip rape (B. rapa L.) and Indian mustard (B. juncea L.). In Ethiopian mustard heterosis over the best-yielding parents in B. juncea by (B. carinata A. Braun), however, information regarding heterosis has crossing parents of Indian and exotic origin. Banga and not been previously reported. This study, therefore, was conducted Labana (1984) reported up to 200% heterosis in B.to generate information on heterosis and combining ability in B.juncea. Brandle and McVetty (1989) reported high-parcarinata. Nine inbred parents and their 36 F 1 s, obtained by half-diallel ent heterosis reaching 120% for seed yield in B. napus. cross, were evaluated for 12 traits at three locations in Ethiopia.In summer turnip (B. rapa), high-parent heterosis for Analysis of variance showed the presence of significant heterosis for seed yield reaching 60% was reported by Schuler et al. all the traits. Seed yield showed the highest relative mid-parent hetero-(1992) and Falk et al. (1994). Consequently, in several sis that varied from 25 to 145% with a mean of 67%. Relative highcountries hybrid cultivars played an important role in parent heterosis for seed yield varied from 16 to 124% with a mean of 53%. General combining ability (GCA) effects were predominant the expansion of B. napus cultivation (Becker et al., in all traits except secondary branches and pods per plant. Specific 1999; Miller, 1999). Heterosis can be partially utilized combining ability (SCA) was significant for days to flowering, secondalso by developing synthetic cultivars (Becker et al., ary branches, pods per plant, pod length, seeds per pod, 1000-seed 1998). weight and oil content. Interaction effects of GCA ϫ location were Although combining ability studies in oilseed Brassica significant for all traits except days to flowering, days to maturity, spp. are scanty, most of these studies emphasized the and oil content. All traits had significant SCA ϫ location interaction preponderance effect of GCA on yield and most of the effects. GCA effect for seed yield was positively correlated with F 1 yield components indicating the importance of additive performance (r ϭ 0.77) and absolute mid-parent heterosis (r ϭ 0.67).

Combining Ability Analysis: Morphological Traits for High Temperature Stress Tolerance in Indian Mustard [Brassica juncea (L.) Czern & Coss.]

“…of secondary branches per plant. Kumar et al, (1997) and Teklewold and Becker (2005) also reported similar results in Indian mustard with a different set of material. The genotype RH0644 in both the environments for main shoot length and RH0644 in normal environment for siliquae on main shoot with significant desirable gca effects were found to be the good general combiners.…”

“…Our findings are in agreement with the earlier results in mustard reported by Singh and Murty (1980), Sheikh and Singh (1998) and Chowdhury et al, (2004a).The magnitude of sca effects for seed yield/plant revealed in crosses viz., RH 8814 x RH0555A, RH 0116 x RH0952, BPR 349-9 x RH0644, BPR 349-9 x BPR543-3 and RH0952 x RH0555A in both the environments, seven crosses in normal and late sown environment showed significant positive sca effects. Teklewold et al, (2005), Nassimi et al, (2006) and Wang et al, (1997) observed significant positive sca effect for seed yield. Significant positive sca effects in both the environments were expressed by only one cross combinations, namely, BPR 349-9 x RH0555A for 1000 seed weight, RH0952 x BPR543-3 in normal and RH 8814 x BPR543-3, RH 0116 x BPR 349-9 and RH 0116 x BPR543-3 in late sown environments oil content.…”

“…Although combining ability studies in oilseed Brassica are scanty, most of these studies emphasized the preponderance effect of gca for yield and its components indicating the importance of additive gene action (Wos et al, 1999). On the other hand, Teklewold et al, (2005) reviewed evidences for the presence of significant sca effects for yield and yield components. Ramsay et al, (1994) reported that variation for both gca and sca were responsible for dry matter yield and other quantitative traits in B. napus.…”

Combining ability of phenological traits and seed yield in spring rapeseed genotypes

“…Likewise, studies with winter cultivars of this species (Amiri-Oghana et al, 2009;Sabaghnia, et al, 2010) showed both additive and dominance gene effects to have a significant role in the inheritance of flowering time. Significant negative GCA and SCA effects were reported for days to flowering (Teklwold .and Becker, 2005).…”

“…Studies on combining ability have been done earlier (Kumar et al, 2011;Nasimi et al, 2006;Singh et al, 2010). Various studies on spring cultivars of oilseed rape have shown the important role of GCA and SCA effects for days to flowering and also it be a highly heritable character determined by genes that exhibit some degree of dominance (Teklwold .and Becker, 2005;Hung, et al, 2010;Zhang and Zhu, 2006). Likewise, studies with winter cultivars of this species (Amiri-Oghana et al, 2009;Sabaghnia, et al, 2010) showed both additive and dominance gene effects to have a significant role in the inheritance of flowering time.…”