为探明不同机插方式下水稻适用穗型和适宜栽插规格,阐明不同机插方式下不同穗型水稻品种产量形成特征,选用大、中和小穗型各2个品种为试验材料,设置钵苗机插(行距33 cm)、行距30 cm毯苗机插和行距25 cm毯苗机插3种机插方式(记为A、B、C),研究机插方式和密度对不同穗型水稻品种产量及其形成和穗部性状的影响。钵苗机插设置3种株距,分别为12 cm、14 cm和16 cm(记为1、2、3),2种行距毯苗机插设置5种株距,分别为10 cm、11.7 cm、13.3 cm、14.8 cm、16 cm(记为1、2、3、4、5)。研究结果表明:1)钵苗机插,随着密度降低,大穗型品种产量呈先增后减,以A2最高;中、小穗型品种产量呈递减趋势,以A1最高。毯苗机插,随着密度降低,大穗型品种B方式产量呈先增后减,以B4最高,C方式呈递增趋势,以C5最高;中穗型品种B和C方式产量均呈先增后减,分别以B3和C4最高;小穗型品种B方式产量呈递减趋势,以B1最高,C方式呈先增后减,以C2最高。同一密度下,钵苗机插产量显著高于毯苗机插,增产幅度表现为大穗型>中穗型>小穗型,2种行距毯苗机插差异不显著。对2种行距毯苗机插而言,同一株距下,大穗型品种B方式产量高于C方式;中穗型品种株距为10 cm、11.7 cm、13.3 cm,B方式产量高,而株距为14.8 cm、16 cm,C方式产量高;小穗型品种除株距为10 cm外,C方式较B方式具有增产优势。2)随着密度降低,不同机插方式下不同穗型品种单位面积穗数减少,每穗粒数增加,群体颖花量变化趋势与产量一致,结实率和千粒重变化不一。同一密度下,不同机插方式间单位面积穗数相当,钵苗机插每穗粒数显著高于毯苗机插,每穗粒数增幅表现为大穗型>中穗型>小穗型,结实率和千粒重差异不显著。对2种行距毯苗机插而言,同一株距下,B方式单位面积穗数少于C方式,而每穗粒数则相反。3)随着密度降低,不同机插方式下不同穗型品种穗长、着粒密度、单穗质量、一次枝梗数、一次枝梗粒数、二次枝梗数和二次枝梗粒数呈增加趋势,一、二次枝梗数比值和一、二次枝梗粒数比值呈减少趋势。同一密度下,钵苗机插穗长、着粒密度、单穗质量、一次枝梗数、一次枝梗粒数、二次枝梗数和二次枝梗粒数高于毯苗机插。因此,钵苗机插应用大穗型品种宜适当降低密度,充分发挥大穗优势,提高群体颖花量而高产;中、小穗型品种宜采用高密度栽插,增加穗数以获得高产。毯苗机插应用大穗型品种宜采用行距30 cm,适当增加株距,依靠扩大穗型而高产;中穗型品种宜采用行距30 cm,配置中等密度,协调穗粒结构而提高群体颖花量;小穗型宜采用行距25 cm,适当减少株距,通过显著增加穗数以获得高产。

In order to apply suitable panicle-typed cultivar and plant density under different mechanical transplantation methods, and clarify high-yield formation characteristics of different panicle-typed rice, an experiment was conducted in Xinghua test point of Yangzhou University during 2013 and 2014. Three panicle-typed rice including large panicle type (LPT, Yongyou 2640 and Yongyou 8), medium panicle type (MPT, Wuyunjing 24 and Ningjing 3) and small panicle type (SPT, Huaidao 5 and Huaidao 10) were field-grown. We compared three mechanically transplanted methods including mechanically transplanted pot seedling (A), mechanically transplanted carpeted seedling in row spacing of 30 cm (B), mechanically transplanted carpeted seedling in row spacing of 25 cm (C) at different plant densities, namely plant spacing of 12 cm, 14 cm and 16 cm (marked as 1, 2, 3) in A and plant spacing of 10 cm, 11.7 cm, 13.3 cm, 14.8 cm, 16 cm (marked as 1, 2, 3, 4, 5) in B and C. Yield and its formation, panicle traits were investigated. The main results were as follows: 1) for mechanically transplanted pot seedling, with declining plant density, yield of LPT increased and then reduced, peaking in A2 treatment; yield of MPT and SPT reduced, peaking in A1 treatment. For mechanically transplanted carpet seedling, with reducing plant density, yield of LPT increased and then reduced in B, peaking in B4 treatment, yield of LPT increased in C, peaking in C5 treatment; yield of MPT increased and then reduced in B and C, peaking in B3 and C4 treatment, respectively; yield of SPT reduced in B, peaking in B1 treatment, yield of SPT increased and then reduced, peaking in C2 treatment. In the same plant density, yield of mechanically transplanted pot seedling was significantly higher than mechanically transplanted carpet seedling, the range of increased yield followed a tendency of LPT>MPT>SPT, with no significant difference in B and C. For B and C, in the same plant spacing, yield of LPT was higher in B than C; yield of MPT was higher in B than C in plant spacing of 10 cm, 11.7 cm, 13.3 cm, but it was opposite at plant spacing of 14.8 cm, 16 cm; yield of SPT was higher in C than B in plant spacing of 11.7 cm, 13.3 cm, 14.8 cm, 16 cm. 2) With plant density reduced, panicle number reduced and spikelet number per panicle increased in different panicle-typed rice under different mechanically transplanted methods. At the same plant density, there was no significant difference in panicle, grain filled percentage and 1000-grain weight in different mechanically transplanted methods, but spikelet number per panicle was significantly higher in A than B or C, following a trend of LPT>MPT>SPT. For B and C, number of panicle was lower in B than in C, but it was opposite in spikelet number per panicle. 3) Panicle length, grain density, grain weight per panicle, number of primary and secondary rachis branches, number of grains of primary and secondary rachis branches were increased with plant density reduced, it was opposite in the ratio of No. of primary rachis branch to No. of secondary rachis branch and ratio of No. of grains of primary rachis branch to No. of grains of secondary rachis branch. In the same plant density, panicle length, grain density, grain weight per panicle, number of primary and secondary rachis branches, number of grains of primary and secondary rachis branches in A than in B or C. Therefore, mechanically transplanted pot seedling of LPT could reduce plant density, it was beneficial to enlarge panicle type and increase total spikelet number and yield; for MPT and SPT, higher density should be adopted to increase panicle and spikelet number per panicle for high yield. For mechanically transplanted carpet seedling of LPT, B method and wider plant spacing should be applied to expand panicle type and acquire higher yield; for MPT, B method and medium density should be applied to coordinate panicle and spikelet number per panicle to increase total spikelet number; for SPT, C method and narrow plant spacing should be applied to increase number of panicle to achieve high yield.