Search Results
Abstract
Fumigations with hydrogen fluoride (HF) decreased in vivo pollen tube growth of ‘Tilton’ apricot (Prunus armeniaca L.). Both tube lengths and percent of styles with pollen tubes that reached the base of the style were adversely affected more by high HF concentration for a short time than by low concentration for a longer time. Pollen germination was unaffected on agar containing sodium fluoride. Fumigations with hydrogen chloride had no effect on pollen tube growth at concentrations from 0.05 to 0.75 mg Cl/m3 and durations of exposure from 8.5 to 72 hours.
Abstract
The muskmelon (Cucumis melo L.) breeding population Wisconsin (Wl) 998 was developed jointly by the U.S. Department of Agriculture, the University of Wisconsin, and Michigan State University to provide breeders and seedsmen with a source from which gynoecious inbreds can be developed for use in the production of hybrid cultivars. In addition to a high incidence of gynoecious plants, WI 998 provides other useful plant and fruit characteristics.
Abstract
The yield-plant density relationships of 5 bush snap bean cultivars and the effect of rate of N application on the yield-density relationship of a single cultivar were studied in 2 separate experiments. Responses were described by the equation W-θ = α + βρ where W is the pod weight per plant, ρ is the plant population density, and θ, α and β are constants. The θ, α and β values were tested for significant differences among the cultivars and levels of N. In experiment 1, θ = 0.836 was acceptable for all 5 cultivars and in experiment 2, θ = 0.897 was acceptable for the 3 rates of N. Values of θ were similar to those found for bush snap beans by other researchers. Significant differences existed among both α and β values of the cultivars. In the N experiment, α was constant but values of β differed significantly and were inversely related to the level of N. Optimum plant density was dependent on the cultivar and increased with the level of N.
Abstract
Tassel date, silk date, plant height, ear height, shank length, husk extension, tip blanking, row number, ear length, and first ear weight were studied in a diallel involving 7 inbred sweet corn parents. Both general combining ability (GCA) and specific combining ability (SCA) were involved in the inheritance of all 10 characters. This was consistent for F1 crosses in 2 years and for F2 families. SCA variance (VSCA) was larger than GCA variance (VGCA) for ear length and first ear weight in the F1 and ratios of VSCA/VGCA for these characters were slightly larger than 1.0. VGCA was larger than VSCA all other characters in the F1. Ratios of VSCA/VGCA ranged from .05 for row no. to .57 for plant height.
Variance ratios for most characters decreased in the F2. The failure of some ratios to decrease in the F2 was attributed to either differential interactions of GCA and SCA with environment or inadequate sampling of F2 families. Genotype × year interactions influenced the expression of most characters. A greater portion of the genotype × year interaction was contained in estimates of SCA than in estimates of GCA. Heritability estimates from parent-progeny regression were generally larger than those from variance components, although these estimates were generally in close agreement.