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Symbiotic nitrogen fixation in peanut offers an alternative way to reduce chemical nitrogen fertiliz-ation. The objectives of this study were to estimate general combining ability (GCA) and specific combiningability (SCA) effects for traits related to N -fixation and agronomic traits and to identify the best parents2for use in peanut breeding programs aimed at improving nitrogen- ixing ability. Full diallel (F ) crosses of 2 peanut with reciprocals involving five parents were planted in a randomized complete block design with four replications. GCA mean squares were more important than SCA mean squares for plant dry weight, nodule dry weight, leaf color score, seed weight per plant, shelling percentage and harvest index. SCA mean squares were significant for pod weight per plant, seed weight per plant and 100 seed weight. SCA mean squares were more important than GCA mean squares for pod weight per plant, and equally important for seed weight per plant. Reciprocal mean squares were significantly important for 100 seed weight, shelling percentage and harvest index. KKU 72-1, (A3-1-1 (Bc 154) (PI 268770) and 42-G-105 (PI 269 109) were identified as good general combiners for traits related to N -fixation, plant dry weight, nodule dry weight and leaf color score, 2 whereas A3-1-1 (Bc 154) (PI 268 770) and KKU 72-1 were the best parents for 100 seed weight. A3-1-1 (Bc 154) (PI 268 770) was also the best general combiner for shelling percentage and harvest index.

Choice of parental lines is primarily important for the ultimate success of breeding programs, while correlation among traits is also useful information when simultaneous selection for multiple traits is considered. The first objective of this study was to estimate general combining ability (GCA) and specific combining ability (SCA) for fresh and dry weight of nodules, pod yield, seed yield, 100-seed weight, pod number per plant and shelling percentage in the F3 generation of 25 peanut crosses derived from 5x5 North Carolina Mating Design II to identify the best parents for these traits. The second objective was to determine correlation among these traits. The experiment was conducted under field condition at Khon Kaen University'sAgronomy Farm. The 25 crosses and their parents were arranged in a randomized complete block design with 2 replications. GCA mean squares were significant for nodule fresh weight, pod yield, seed yield, 100-seed weight, pod number per plant and shelling percentage, whereas SCA mean squares were not significant for these traits, indicating the importance of additive gene effects governing the inheritance of these traits. PI 269109 had high GCA effects for nodule fresh weight, 100-seed weight, pod number per plant and shelling percentage, and PI 243574 had good combining ability for pod yield and seed yield. KK 60-3 was identified as good general combiner for nodule fresh weight, pod yield, seed yield and 100-seed weight. High and positive phenotypic correlation was found between nodule fresh weight and nodule dry weight. Pod yield,seed yield and 100-seed weight were positively correlated with each other.

A total of 791 animals involved in Thai Native (T), Boer (B), Saanen (S) and their crosses were studied. Fixed effects of sex, birth type, breed group and year-season of birth were found to significantly affect birth weight (BW), weaning weight (WW) and average daily gain (ADG) (P < 0.05). Two statistical models were analyzed in this study. The first model showed that the B breed had higher BW and the S breed had highest WW and ADG than the others (P < 0.05). The T breed had the lowest BW, WW and ADG (P < 0.05) among all breeds and breed crosses. Direct additive and maternal breed effects of B and S breeds from Model 2 had significantly positive values (P < 0.05). It indicated that the B and S purebreds had heavier body weights than the T breed. Direct heterosis, maternal heterosis and recombination effects were not significant. The heterosis estimates of crossbreeding between S and T purebreds tended to yield heavier weaned kids (P > 0.05). Estimated direct and maternal heritabilities were found to be 0.25 and 0.08 for BW, 0.38 and 0.11 for WW and 0.35 and 0.12 for ADG. The direct genetic, maternal genetic and phenotypic correlations among pre-weaning traits were positive with moderate to high values (0.30 to 0.89). The findings provided basic information that farmers and breeders could utilize for an appropriate approach to crossbreeding and monitoring the genetic potential in this herd.