Effect of different mechanical direct seeding methods on tiller characteristics and yield of rice

Abstract: Little information is available on tillering characteristics and their relationships with high yield in the different patterns of water mechanical-direct-seeding cultivation in rice have not been understood. The experiments were conducted using four varieties, conventional rice Changnongjing 7, super rice Nanjing 44, hybrid rice Yongyou 2638, and Yongyou7, to investigate the characteristics of tillers emergence and panicle formation and its productivity and contribution to yield by the two mechanical-direct-seeded planting patterns - hole seeding and seeding in drill cultivation. The results indicated that the tillers emergence and the panicle rates were significantly affected by the different mechanical-direct-seeding patterns. In the two planting patterns, the leaf position number of tillers emergence in the main stem were five, namely leaf 1/0 to leaf 5/0 and secondary tillers group emerged mainly in 1/1, 2/1, and 1/2 with the difference in four varieties. The percentage of primary tillers emergence of different leaf positions in hole seeding pattern was lower than that of seeding in drill pattern, but was higher than the percentage of secondary tillers emergence. The percentage of primary tillers emergence in 3/0 and 4/0 was 100%. Tertiary tillers and even more grades tillers did not initiate in the two planting patterns. The grain yield of all four rice varieties under the hole seeding pattern was higher than that of the seeding in drill pattern (p<0.05), and the different planting patterns affected the earbearing percentage of tillers and their contribution to high yield (p<0.05). The tillers of 1/0 to 5/0 in the main stem were able to earbear, among them 1/0 to 3/0 were main leaf positions with higher percentage of panicle formation (more than 50%), and the percentage of panicle formation of the hole seeding cultivation was higher than that of the seeding in drill cultivation. The main leaf positions of panicle formation of secondary tillers were 1/1 and 1/2 with a very low earbearing percentage, and earbearing percentage of the hole seeding pattern was lower than that of the seeding in drill pattern. The percentage of yield of primary tillers group contribution to total population yield was significant in different tillers (p<0.05) and the tiller 3/0 had maximum productivity and contributive proportion, and the contributive proportion of tillers in the hole seeding pattern was higher than that of the seeding in drill pattern. But the contributive proportion of the secondary tillers was lower with the trend of the hole seeding pattern higher. By analysis of characteristics of panicles and spikelets, in tiller 3/0 the panicles number per area and spikelets number per panicle were bigger, and the hole seeding pattern had bigger spikelets number per panicle than the seeding in drill pattern. The appropriate production application and available regulation approach of the different patterns of water mechanical-direct-seeding cultivation in rice, such as management measures of manure and water, etc., are also discussed in the present paper. The experiment indicates the rules of tillers emergence and panicles formation for rice in water mechanical-direct-seeding cultivation, which provides a theoretical basis for high yield of the farm equipment in field production.