Search Results
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
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.
Abstract
The extent of intraspecific variability for N2 fixation among 100 southernpea (cowpea) genotypes was determined, and a screening technique was developed to measure the character. Significant differences in N2 fixation efficiency were found among host plant genotypes following application of a standard commercial mixed strain Rhizobium inoculant. These differences were obtained whether the criterion used was nodule mass, nodule number of nitrogenase activity, as measured by the acetylene reduction assay. This variability is evidence of genetic control of the trait and suggests the possibility of breeding for increased N2 fixation efficiency in cowpea.