Abstract:

The aim is to explore the utilization value of high tillering characteristics of rice mutant material W33 in rice breeding. Wild-type rice restorer line R818 and its mutant W33 with higher-nodal-position tillers were served as the test object, and potting experiment was used to study the difference of plants, tiller and panicle traits of R818 and W33, the difference of tiller, yield composition characters and grain yield of R818 and W33 were compared by field cultivation experiment, the character data of the test materials were measured. The results showed that there was no significant difference in plant height and average leaf length of main stem between W33 and R818 at the early stage of growth, and however there was significant or extremely significant difference in plant height and average leaf length of main stem between the two in the middle and late period; the average tiller number per plant of W33 was 7.5-8.8 times that of R818, the average effective panicle number of W33 was 8.6 times that of R818, and the average percentage of earring-tillers was equivalent to that of R818, but the length of single panicle, the number of branches per panicle and the number of grains per panicle were much lower than those of R818, while the 1000-grain weight slightly differed from that of R818. The grain yield per plant of W33 and R818 decreased with the density increased, it was the highest when the density was the lowest, and it was the lowest when the density was the highest. Although the yield per panicle of W33 was much lower than that of R818, there was no significant difference of population yield of W33 and R818 under the same density (Fvalue=3.7868<F_0.05,1,4). Within a certain density range, the advantages of vigorous tillering ability and higher spikes rate of W33 could be fully demonstrated to make up for its disadvantage of low yield per panicle, and its population yield could finally reach the level equivalent to that of R818. It is suggested that the characteristics of stronger tillering ability and higher spikes rate of W33 should have certain utilization value in rice breeding.

Key words: rice, mutant material, tillering traits, tiller number, effective number of panicles, utilization value