No abstract

Development, fecundity, and longevity of the predator, Orius insidiosus (Say) (Heteroptera: Anthocoridae), when reared on greenbug [Schizaphis graminum (Rondani)], cotton aphid (Aphis gossypii Glover), or eggs of tobacco budworm [Heliothis virescens (F.)] with green beans or water were examined. Developmental time was shortest when predators were reared on H. virescens eggs and beans and longest when reared on cotton aphids and water. Predators were most fecund when fed H. virescens eggs. The inclusion of beans in the nymphal diet further enhanced fecundity when fed eggs. Longevity of both females and males was significantly shorter when reared on aphids than on eggs. Beans in the nymphal diet enhanced longevity of female predators only in combination with budworm eggs. Female O. insidiosus were largest when reared on H. virescens eggs. Addition of green beans in aphid treatments resulted in increased size of O. insidiosus when compared to aphids and free water.

Succulence or water content was used as an index for selection to improve forage quality of Lolium‐Festuca hybrid derivatives. Leaf‐roll, moisture content, and in vitro dry matter digestibility, determined during drought stress, were used as selection criteria to isolate succulent parents of ‘Kenhy’ and an experimental strain, G1‐307. Kenhy and G1‐307 had significantly less leaf‐roll; higher moisture content, palatability, and digestibility; lower acid‐detergent‐fiber content than ‘Kentucky 31’ and ‘Fawn’ tall fescue (Festuca arundinacea Schreb.) when all were compared in field plots. Stomata in Kenhy had a smaller pore size and a lower frequency per unit area than those in Kentucky 31, which may account for differences between the two cultivars in leaf‐roll and succulence characteristics. A positive relation was observed among moisture content, digestibility, and palatability. Moisture content was negatively correlated with acid detergent fiber. An analysis of variance for moisture content of parents and progenies of G1‐307 indicated that this characteristic was sufficiently heritable to permit improvement of forage quality of tall fescue through breeding.

No abstract

Breeding tall fescue (Festuca arundinacea Schreb.) cultivars with high digestibility and high nonstructural carbohydrate content and the proper balance of potassium (K), calcium (Ca), and magnesium (Mg) may overcome many of the seasonal problems of cattle grazing the species. The objective of this paper is to present estimates of genetic variability and heritability of digestibility, water‐soluble carbohydrates, K, Ca, Mg, and the K/(Ca + Mg) ratio and their association in selected Lolium‐Festuca hybrid derivatives. Twenty‐eight parental clones were evaluated in a spaced plant nursery, and their polycross progenies (pep) in seeded rows in Madison County, Kentucky. Additionally, the pcp were evaluated in sod plots in Fayette County, Kentucky. A combined analysis of variance of parents and pep at both locations for forage quality and mineral constituents showed highly significant differences for these characteristics among selections, generations, years, and their interactions. Broad sense heritahility estimates among parental clones were high for all constituents, indicating that a considerable portion of the total variability was genetic. Heritability estimates obtained from regression of pcp on parents were relatively high when parents and pcp were grown in close proximity for all constituents except K and the K/(Ca Mg) ratio. When parents and pcp were grown in widely different environments, the heritability estimates were low for all constituents. Thus, breeding materials should be evaluated for forage quality and mineral constituents in a minimum of two locations with widely different environments. Predictions of response to selection were disappointingly small for all characters. The data suggest that progress in breeding for low tetany potential in these materials, while possible, may require considerable time and effort.