Effect of source-sink limitation on agronomic traits and grain yield of different lines of rice (Oryza sativa L.)

In order to study the effect of source-sink limitations on agronomic traits and grain yield of different lines of rice, a field experiment was carried out as factorial in a randomized complete block design with four replications in Chaparsar Rice Research station of Mazandaran province in 2013. Treatments of source-sink limitation in four levels (including cutting of flag leaf, cutting of one third the end of panicle, cutting of other leaves except flag leaf and control or without limitation) and lines of rice in four levels (line of No. 3, line of No. 6, line of No. 7 and line of No. 8) were the treatments. Among different lines, the maximum 1000-grain weight and panicle fertility percentage were obtained in lines of No.7 (33.3 gr) and 8, respectively. The maximum panicle length (29.7 cm), number of fertile tiller per plant (21.4 N.o) and unfilled grain number per panicle (71.5 N.o) were observed in line of No. 3, but the line of No.6 had the highest total grain number per panicle (210.9). Among different source-sink limitation treatments, increased the panicle length and unfilled grain number per panicle and decreased the panicle fertility percentage, when all leaves except flag leaf removed. Also interaction effect of two factor showed that the highest grain yield (6531 kg.ha-1 was obtained in line of No.7 and control treatment. The lowest grain yield (4166.3) kg.ha-1 was observed in line of No.6 and cutting of leaves except flag leaf. In general, it can be concluded that among lines, the line of No.7 had the sink limitation and other lines (No.3, No.6 and No.8) had the source limitation.