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- Author or Editor: J. C. Miller Jr. x
Abstract
Flower bud abortion, which can influence crop maturity, has been observed in gynoecious and/or predominantly pistillate strains of cucumber (Cucumis sativus L.) Pre-anthesis abortion was completely dominant to non-abortion. The flower bud abortive trait tentatively assigned the symbol Fba was shown to be linked with femaleness with an average map distance of 18 crossover units.
Abstract
Early and late flowering cultivars of cucumber (Cucumis sativus L.) and their progenies were used to determine the inheritance of the time required to reach anthesis and its importance as a component of earliness. Genetic variance was primarily additive; however, partial dominance for early flowering and low nodal position of the first flower was noted. Days to first flower appeared to be controlled by relatively few genes, and heritability estimates for this trait were moderately high (0.46 to 0.62). Number of days to flowering was found to be more important in early crop maturity than was rate of seedling emergence. Lower temperatures delayed flowering, and thus maturity, by slowing plant growth and raising the node number at which the first flower appeared. A significant correlation coefficient of 0.82 was obtained between flowering time and mean maturity date.
Abstract
In the paper “Comparison of Two Methods of Hand-crossing Vigna unguiculata (L.) Walp” by K. W. Zary and J. C. Miller, Jr. [HortScience 17(2):246-248. 1982] there is an editing error in the abstract. Crossing method 1 should read “method 2” and method 2 should read “method 1.”
Abstract
Five lines of cowpea were crossed in a complete diallel, using 2 methods. Crossing success rate was greatly enhanced by collecting pollen donor flowers on the morning of anthesis, storing them until late afternoon, and then completing the cross on freshly emasculated flowers (method 1) as compared to utilizing pollen donor flowers for crossing immediately upon collection, early to mid-morning on the day of anthesis (method 2). Significant differences in success rate were found among cultivars used as seed parents in method 2, while no such differences were observed in method 1. Significant differences in success rate were found among cultivars used as pollen parents in both methods.
Abstract
Anatomical examination of 1-day preanthesis ovaries of pickling cucumber (Cucumis sativus L.) showed that, at this stage of development, structural characteristics were not associated with propensity of cultivars for carpel separation. However, at a later stage of development, just before visible separation occurs (4 cm diameter fruits) varietal propensity for separation was associated with large cell size along ventral carpel structures, cell collapse, and the formation of microscopic cavities. Morphological studies showed that in cultivars with a strong tendency for carpel separation, the splitting of ventral carpel surfaces began at an earlier stage of fruit development than in cultivars with only a moderate tendency for separation.
Abstract
Diurnal and seasonal patterns of nitrogen fixation N2(C2H2) in southernpea were delineated, using 7 genotypes which differed in potential to fix nitrogen. Diurnal activity peaked at 1200 hours, at both 34 and 53 days after planting (DAP). Significant differences in total activity between genotypes were observed, with maximum activity generally coincident with full flowering. High fixing genotypes were higher in total nitrogenase activity throughout the growing season, than were the low fixing genotypes. Peak activity for the latter was found at 34 DAP, while the former peaked at 46 DAP. Mean nodule mass, nodule number and plant dry weight were greatest 53 DAP.
Methods for detecting and mathematically regressing daily tall fescue (Festuca arundinacea Schreb.) leaf appearance on environmental variables are presented. Morphological stages of leaf development were quantified and the rate of leaf appearance was linearly regressed on environmental variables. The following model was developed to predict daily tall fescue leaf appearance and was successfully tested on unrelated data: Daily leaf appearance rate = 0.016 – (2.48 × 10-4 × solar radiation) + (0.015 × precipitation 2-day lag) + (0.117 × soil moisture 3-day lag) + (8.79 × 1 0-6 × maximum air temperature × solar radiation) - (3.61 × 10-' × maximum air temperature × age) + (0.00307 × minimum air temperature × precipitation) – (4.39 × 10-4 × precipitation × age), (R2 = 0.78). Growers of tall fescue and researchers will benefit in the identification of environmental characteristics and cultural practices that significantly influence leaf appearance rate.
Abstract
Rhizobial inoculation with commercial cowpea ‘EL’ mixed strain inoculant as compared to noninoculation, and effects of four levels (0, 14, 28, and 84 kg·ha−1) of fertilizer N (CaNO3–15.5% N) on yield and N2 fixation components in cowpea [Vigna unguiculata (L.) Walp.] were investigated in a field study. Plants were grown on a vertic albaqualf, fine, montmorillonitic, thermal soil with a pH of 6.7. Three high (H) and two low (L) N2-fixing, indeterminate cowpea cultivars, ‘H-California Blackeye No. 5’, ‘H-Brown Crowder’, ‘H-Tennessee White Crowder’, ‘L-Lady’, and ‘L-Mississippi Silver’, were used. In inoculated plants, N2 fixation was significantly reduced with increasing N levels. Although high-fixing cultivars produced more and larger nodules and expressed higher nitrogenase activity than the low fixers, no significant differences in top dry weight and total N/plant were observed between these groups at the time of flowering. Seed yield was greater in rhizobia-inoculated plants than in the noninoculated, fumigated controls. A significant linear increase in seed yield was observed with increasing N levels in the noninoculated, fumigated controls. The addition of fertilizer N to cowpeas inoculated at planting did not increase seed yield. In high-fixing cultivars, N2 fixation did not directly influence seed yield, but increased vegetative matter was produced. Seed and biomass yield were influenced by N2 fixation in low-fixing cultivars.