Evaluation of seed filling problems in some hybrids and open-pollinated sun flower (Helianthus annuus L) cultivars, as affected by pollination and sowing dates

Abstract

A field experiment was conducted at the College of Agricultural Studies, Sudan University of Science and Technology, Sudan, Khartoum, during summer 2014 and 2015, to study the effects of sowing date, pollinations and cultivars on seed setting and seed filling of sunflower (Helianthus annuus L).The cultivars were Hysun33 and local .The experiment was factorial experiment with three factors in a randomized complete block design (RCBD) with four replications. Two cultivars, local (PAN-7351 LC) and hybrid (Hysun-33) were used. Plants were grown in three different sowing dates (March, May, JulyS1 S2 S3)and two type of pollination(open pollination and cover pollination). Growth parameters studied were Plant height, leaf area, number of seeds setting/head, number of seeds filling/head, hundred seed weight , hundred seeds filling weight, head diameter, dry weight, seeds setting (%),seeds filling %and The efficiency. The results showed that sowing dates were highly significant for most of the parameters in both seasons ( leaf area, number of seeds filling per head, head diameter, dry weight).The sowing date revealed highly significant effect in season one, namely in number of seeds setting per head, seeds setting percentage and the efficiency. Significant differences between the two types of pollination were revealed in some characters in first season namely plant height, number of seeds setting per head, , number of seeds filled per head, seeds filling percentage, Seeds setting percentage and the efficiency and highly significant differences on weight of hundred seeds setting. Moreover, analysis of variance indicated highly significant effects of pollination on most characters, number of seeds setting per head, number of seeds filling per head, weight of hundred seeds filling, head diameter, dry weight, seeds setting percentage, seeds filling percentage and the efficiency in second season. Also there were significant differences among sunflower cultivars in plant height which was highly significant in season two. The analysis of variance indicated highly significant differences among sunflower cultivars in most yield and yield components, namely number of seeds setting per head, , number of seeds filling per head, weight of hundred seeds filled, seeds setting percentage.