Mehdi Joudi; shahram mehri
Abstract
The aim of this research is to study the pattern of dry matter partitioning to different above-ground plant parts during anthesis, two weeks after anthesis, and physiologic maturity among wheat cultivars and to investigate its possible relationship with grain yield. Eighteen well-watered wheat cultivars ...
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The aim of this research is to study the pattern of dry matter partitioning to different above-ground plant parts during anthesis, two weeks after anthesis, and physiologic maturity among wheat cultivars and to investigate its possible relationship with grain yield. Eighteen well-watered wheat cultivars have been grown at research farm of Moghan College of Agriculture and Natural Resources based on randomized complete block design with three replications during 2014-2015 growing season. At anthesis, total dry matter accumulated in the plant, range from 1.95 (Sumay3) to 3.33 g (Alvand). At this time, depending on the cultivar, dry matter partitioned to the stem which differ from 31% to 41%, vary from 37% to 50% in the leaves, and from 16% to 27% in the spike. From anthesis to two weeks post-anthesis, dry weight of stem and spike increase, while those of leaves, generally, remain constant. The highest (1.52 g) and the lowest (0.52 g) increases in the weight of stem and spike have been observed in the case of Shirodi and Sardari, respectively. During two post-anthesis weeks to physiologic maturity, the spike has been dominant; however, the cultivar differences in the amount of allocated photoassimilates to the spike as well as stem reserves remobilization change the pattern of dry matter partitioning among wheat population again. At anthesis, there has been no clear association between cultivar height and spike weight. At physiologic maturity, however, dwarf cultivar generally has had higher weight and proportion of the spike. These results show that the pattern of dry matter partitioning is varied depending on the plant developmental stages and cultivars. Therefore, partitioning pattern of a cultivar observed at one growth stage is not necessarily similar in other growth stages. At physiologic maturity, Crossed Alborz and Pishtaz are superior with respect to dry matter partitioning and yield performance. Analysis of correlation reveals that leaves dry weight at anthesis, stem dry weight at two weeks after anthesis, and partitioned photoassimiltes to the grain are correlated positively with square grain yield. Therefore, these traits deserve further attentions in wheat programs dealing with increased grain yield.