Keith W. Hendrix

Content of Some Nutrients in the Core of the Core of the Peanut Germplasm Collection

Abstract The usefulness of core collections of germplasm collections has been well established. The U.S. germplasm collection for peanuts was selectively reduced based on morphological characteristics to a mini core or “Core of the Core” collection composed of 112 of the 7432 accessions in the whole collection to make it more efficient for study. Of these samples, 108 were available from one location in the same year and were therefore exposed to one set of environmental conditions wherein genetic variability could also be examined. These samples were analyzed for total and individual amino acid content, fatty acid content, tocopherols, and folic acid content. These data provide a starting point for establishing nutrient composition within these accessions and provide an early indication of currently important characteristics in these lines which might be suited for use in random breeding initiatives.

Genotype-by-Environment Interactions for Seed Composition Traits of Breeding Lines in the Uniform Peanut Performance Test

Peanut composition is influenced by several groups of factors: environmental, genetic, and their interaction. This study evaluated the relative contributions of these factors using data from the USDA-ARS quality testing program using samples from the multi-state Uniform Peanut Performance Tests (UPPT). Data were subjected to restricted maximum likelihood estimation of variance components reflecting the main effects of year, production region, location within region, genotype (cultivar or breeding line), and kernel grade (‘‘seed size’’) within genotype, and the interactions among these main effects. Genetic variation in oil content was low (9% of total variation); however, fatty acid composition of the oil was highly influenced by genotype (34–77%) with the exception of lignoceric acid (1%). Genetic influence on tocopherols was generally less than that of fatty acids. Environmental variation of tocopherols was greater than the variation attributable to genotype-by-environment interaction. The lowest genetic variation was observed in sugar content; however, environmental variation was high (68%). The magnitude of genetic influence on oil content and fatty acid concentrations suggests that these traits are amenable to improvement through breeding.

Effect of Feeding by a Burrower Bug, Pangaeus bilineatus (Say) (Heteroptera: Cydnidae), on Peanut Flavor and Oil Quality

A burrower bug, Pangaeus bilineatus (Say) (Heteroptera: Cydnidae), is known to feed extensively on peanut, Arachis hypogaea L., pods; particularly under certain reduced tillage production conditions. These bugs produce a strong odor when infested peanuts are uprooted, and previous anecdotal evidence indicated that burrower bug feeding is detrimental to peanut flavor. Various levels of burrower bug kernel feeding (0, 5, 10, 25, and 50% of seed by weight) were evaluated for effects on peanut flavor and oil quality. Burrower bug feeding had no detrimental effect on flavor as determined by trained panelists using descriptive sensory analysis. There was a slight, but measurable effect on oil quality as determined by a decrease in oxidative stability and an increase in peroxide values with increased levels of feeding. There was no measurable effect on free fatty acid content or fatty acid profile at the feeding levels tested. The data indicate that incidental feeding (<20% of seed) by this pest is unlikely to be detrimental to peanut flavor. At higher feeding incidence levels, the potential risks of direct yield loss, grade reductions, and aflatoxin contamination are of greater significance than concern for relatively minor reductions in oil quality.

Intensities of Sensory Attributes in High- and Normal-Oleic Cultivars in the Uniform Peanut Performance Test

ABSTRACT In order to ascertain whether or not flavor differed between high- and normal-oleic peanuts (Arachis hypogaea L.), data from the quality assessment phase of the Uniform Peanut Performance ...

Differences in Development of Oleic and Linoleic Acid in High- and Normal-Oleic Virginia and Runner-Type Peanuts

ABSTRACT A consistent, pure supply of high-oleic (HO) peanuts is important to certain segments of the food industry as it allows for the production of confections and other products with improved s...

Microstructures of Oil Roasted Peanuts (Arachis hypogaea L. cv. VA 98R) as Affected by Raw Moisture Content

Raw runner type peanuts were dried to moisture levels of 4.24 or 6.62 %. Each batch was oil roasted at 160°C in pure peanut oil for the amount of time determined to produce a surface color of 48 on the Hunter L scale. The surfaces of the cotyledons were examined by scanning electron microscopy. Escaping steam caused ruptures in the surfaces during the roasting process. The higher moisture samples had more complex tears to the outer surface as a result of higher amounts of steam escaping from the interior. The interior cell components were found to be more distorted and compacted at a moisture level of 4.24 %. Although it was found that in peanuts, shorter heating times were required to reach the desired color at the higher moisture, the large amount of escaping steam resulted in more surface cell destruction than at the lower moisture. The lower moisture samples appeared to have more interior cell damage. This might have an effect on the retention of oil by the peanuts.

Genotype-by-Environment Interactions for Flavor Attributes of Breeding Lines in the Uniform Peanut Performance Test

Peanut flavor is influenced by several groups of factors: environmental, genetic, and interaction between them. This study evaluated the relative contributions of these factors using data from the USDA-ARS program of sensory quality testing of samples from the multi-state Uniform Peanut Performance Tests (UPPT). Data were subjected to restricted maximum likelihood estimation of variance components reflecting the main effects of year, production region, location within regions, genotype, and kernel grade within genotype, and the interactions among these main effects. Genetic variation was relatively small (0.0 to 9.5% of total variation) while environmental variation, particularly that due to years, was large. Year-by-genotype interaction was large for roast color and intensities of the roasted peanut and sweet aromatic attributes. Estimates of repeatability (R) for sensory attributes were low, even based on means measured across multiple locations and two years, except for that of the sweet attribute (R 5 0.10 for a single observation and R 5 0.34 for a mean across two years of UPPT testing). Breeders should be able to reliably identify lines with superior sweet attribute intensity, but identification of lines with intense roasted peanut attribute will be more difficult.