Impact of Plant Density and Leaves Defoliation of Sunflower Intercropped with Sugar Beet on The Productivity of Both Crops and Competitive Relationships تأثير الکثافة النباتية وتوريق دوار الشمس المحمل على بنجر السکر على إنتاجية کلا المحصولين والعلاقات التنافسية

Abstract

This research was done to evaluate the growth and yield of potato plants raised from seed tuber pieces (STP) containing one, two, three and four eyes, for ascertaining whether seed tuber pieces containing two eyes will sustain potato growth and yield indifferently from those of larger seed tuber pieces containing more eyes. Results indicated that number of stolons and leaves per plant, leaf area, plant fresh and dry weight, relative growth rate, net assimilation rate, crop growth rate, chlorophyll a, b as well as total chlorophylls, Number of tubers and total tuber yield per plant were decreased with decreasing number of eyes in the STP. However, final emergence percentage and total carotenoids content were not significantly affected. Nevertheless, number of tubers and total tuber yield per plant did not differ significantly neither between whole seed tubers and half seed tubers containing four eyes nor half STP containing three eyes and quarter STP containing two eyes. However, all these parameters were significantly lower in response to single-eye STP compared with those containing two eyes or more. From the economic point of view, cultivation of quarter STP containing two eyes instead of half STP containing four eyes represents 50 % conservation in the seed tubers used for only 13.5 % loss in tubers yield. So, it could be concluded that the gain in net income became substantiated by cultivation of quarter STP containing at least two eyes instead of larger seed tuber pieces, even that represents half of the seed tuber.