No abstract

‘Webb’ (Reg. No. CV‐120, PI 667551) is a high‐yielding, high‐oleic fatty acid, nematode‐resistant peanut (Arachis hypogaea L. ssp. hypogaea var. hypogaea) cultivar that also has a moderate level of resistance to Sclerotinia blight (caused by Sclerotinia minor Jagger). The cultivar was developed in the Texas peanut breeding program and released by Texas AgriLife Research to serve peanut growers who have infestations of root‐knot nematode [Meloidogyne arenaria (Neal) Chitwood] and are required to have a peanut with a high ratio of oleic acid to linolenic acid to offer for sale. Webb has larger pods and seeds than most other lines released from the Texas peanut breeding program, but it is similar in size to ‘Tamrun OL 01’, which was released in 2001. Webb has performed well in 19 yield tests across 5 yr, and it has good blanching and shelling characteristics. The seed‐size distribution is in the acceptable range for a runner peanut, as expected by shellers and manufacturers. Flavor components of Webb were found to be acceptable, with no off flavors and a high roasted‐peanut flavor score. Webb is the third cultivar released by the Texas program resulting from the introgression of root‐knot nematode resistance from wild peanut species.

The current interest in biodiesel production has resulted in a concurrent interest in increasing the oil concentration in high-yielding cultivars, which could make peanuts ( Arachis hypogaea.) more desirable as a biofuel source. Currently, peanut seed is approximately 450 to 500 g kg −1 oil on a dry weight basis, depending upon location grown, and there is relatively little genetic variation for oil concentration among adapted high-yielding cultivated peanut genotypes. Thus, identifying sources of variation and elucidating the genetics of oil concentration in peanut is essential to advancing the development of high oil genotypes. The objective of this study was to determine the types of gene action governing the inheritance of oil concentration in peanut by generation means analysis. The F 1 , F 2 , and backcross generations of two different runner peanut crosses segregating for oil concentration were evaluated in College Station, Texas, in 2010. Significant differences in oil concentration among the generations were detected, and generation means analysis revealed significant additive, dominance, and epistatic effects for oil concentration in both crosses. The broad-sense heritability estimates were 0.85 and 0.78, and narrow-sense heritability estimates were 0.55 and 0.53 for each of the crosses. Our data indicate that transgressive segregants for high oil were observed, and there is sufficient additive variation present to improve the oil concentration of current runner cultivars.

Peanut (Arachis hypogaeaL.) has the potential to become a major source of biodiesel, but for market viability, peanut oil yields must increase. Oil yield in peanut is influenced by many different components, including oil concentration, seed mass, and mean oil produced per seed. All of these traits can potentially be improved through selection as long as there is sufficient genetic variation. To assess the variation for these traits, a diallel mating design was used to estimate general combining ability, specific combining ability, and heritability. General combining ability estimates were significant for oil concentration, weight of 50 sound mature kernels (50 SMK), and mean milligrams oil produced per SMK (OPS). Specific combining ability was significant for oil concentration. Reciprocal effects were detected for OPS. Narrow-sense heritability estimates were very high for oil concentration and 50 SMK and low for OPS. The low OPS heritability estimate was caused by the negative correlation between oil concentration and seed size. Consequently, oil concentration and seed mass alone can be improved through early generation selection, but large segregating populations from high oil crosses will be needed to identify progeny with elevated oil concentrations that maintain acceptable seed sizes.

No abstract