| Tiller,which affects the number of panicle and the grain production,is an important agronomic trait of rice,and also a special branch in monocotyledonous plants.The growth of tiller is a complicated process,a lot of factors affect tiller occurs,including the natural environment,plant nutrition and the levels of hormone,but s the genetic factors are the most important one.The study on the characteristics of tillering in rice under different genetic backgrounds is of great significance for the effective regulation of tiller occurrence and breeding of high yield rice varieties.In order to explore the difference of tillering characteristics,we compare and analyze the tiller dynamics and main agronomic traits based on 45 rice varieties.We find that the tillering characteristics among varieties are very different,based on 45 rice varietues,by comparing and analyzing the tiller dynamics According to the emergence time of the maximum number of tillers,the experimental varieties are divided into three categories.The tiller of the first-species varieties occurred rapidly during the early days in tillering stage,and reach the maximum number at the 45th day after sowing.For the second-species varieties,the growth of tiller was relatively slow on early days,followed by a fast growing period,and reached the maximun number of tillers at the 52th day after sowing.The tiller numbers of the third-species varieties continue to grow till the 59th day after sowing,and there was no clear active tillering period throughout the whole tillering stage,and the number of tillers in most of the species was over than 10.There was no significant difference in tiller speed between three categories.At the time of tillering,the first-species varieties was the earliest,followed by the second-species,and the tiller of the third-species was latest.We studied the relationship between the number of tiller and the days after sowing by regression analysis,and predicted the date of tiller start and reach the maximum number.The results showed that the tillering time of the first-species was more concentrated and the second-species was moderate,while the third-species was more dispersed.For our breeding work about "early tiller" rice varieties,the rice cultivars with ashorter tillering time and faster tillering speed and moderate tiller number are the most preferred rice varieties.For this reason,the first-species was the best,followed by the second-species varieties,and the third-species was inappropriate.The correlation analysis was carried out on 15 major agronomic traits of 45 rice cultivars,the results showed that the effective panicle number of rice was positively correlated with the number of tiller,and the spike rate was negatively correlated with the number of tiller.There was a negative correlation between the number of spikelets per panicle and the number of tillers,especially negatively correlated with the number of later tillers.In addition,the dry weight of single stalk was negatively correlated with tiller numbers at maturity,but positively correlated with the number of spikelets per panicle.We did a cluster analysis of all the rice varieties,and 45 varieties was classified as A?B?C and D according to the genetic distance.The tillers number of the C-category was about 6.75,and the average number of spikelets per panicle was 309.28,which belonged to high yield varieties with few tiller number,ear height and tiller.The D-category are similar to those of C,but the number of tillers is slightly higher,and the number of spikelets per spike is less.While the A-category and B-category have mores stronger tillering ability,and most of the tillers occurred later,the dry weight of single stalk and the number of grains per spike was also smaller.In conclusion,our study group suggested that the rice varieties with moderate tiller number,more earlier tillering,earning earlier and little difference in ear size,which was beneficial to the structure optimization and yield improvement of rice The... |
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