|Isleib, Thomas - NC STATE UNIVERSITY|
|Giesbrecht, Francis - NC STATE UNIVERSITY|
Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 23, 2003
Publication Date: N/A
Interpretive Summary: Improving peanut flavor is a goal of peanut breeders. Use of parents that have a proven high transfer of positive flavor traits is a useful means of improving a single trait like roasted peanut flavor or sweet taste. We used a line that had superior flavor characteristics (NC Ac 18431) in a cross with a standard cultivar (NC 7). The results indicated that the increases in specific flavor traits in these progeny would be very limited. These data suggest that examination of later generations, when families are stable, might be a better place to select for improvements in flavor characteristics.
Technical Abstract: The sweet, bitter and roasted peanut attributes of roasted peanut (Arachis hypogaea L.) flavor have been shown to be heritable traits. Previous research has estimated broad-sense heritability (H) and breeding values of numerous peanut cultivars and breeding lines for these attributes, but no study has estimated narrow-sense heritability (h2) in a specific population derived through hybridization and inbreeding. A population of 120 F3-derived families was developed without selection from the cross of NC 7 with NC Ac 18431, a virginia-type line identified in 1990 as having a good flavor profile. The parents and F3:5 families were grown at two locations in North Carolina in 1995. SMK samples from each plot were roasted, ground to paste, tasted by a sensory panel, and scored for roasted peanut, sweet, bitter and astringent attributes. Additive and nonadditive genetic variances were estimated by equating variances among F2-derived families and among F3-derived families within F2-derived families to genetic covariances among inbred relatives. Regardless of whether the genetic model included dominance or additive-by-additive epistasis, the estimates of additive genetic variance for flavor attributes were small compared to those for nonadditive genetic variance. Narrow-sense heritability in the F2 generation was estimated at 0 for roasted peanut and astringent, 0.02 to 0.04 for sweet, and 0.01 to 0.03 for bitter, depending on the model used. Because of the low values of h2, which are specific to this population, gain from selection in early generations is expected to be limited within this population. Selection in this population should be practiced in late generations. Other parents have been identified whose crosses should produce greater improvement in sensory quality than can be expected from the NC 7/NC Ac 18431 population.