Growth and physiological responses of super hybrid rice Liangyoupeijiu to tillage and crop establishment methods.

摘要

Super hybrid rice, Liangyoupeijiu was grown in conventional tillage transplanting (CTTP) and no tillage transplanting (NTTP) at a spacing of 20x20 cm with one seedling per hill and conventional tillage direct-seeding (CTDS) and no tillage direct seeding (NTDS) at a seeding rate of 22.5 kg/ha to compare the growth and physiological responses during 2011-12, in Changsha, Hunan Province, China. Our results indicated that leaf area index (LAI) was higher at booting stage (BT) in transplanting (TP) and at HD stage in direct seeding method (DS) both CT (conventional tillage system) and NT (no tillage system). Leaf area duration (LAD) was higher in DS both CT and NT. Specific leaf area (SLA) and leaf area ratio (LAR) were higher at early growth stage both TP and DS either CT or NT then gradually decreased with advancement of time. DS produced more above ground biomass than TP but at maturity, both CTTP and NTDS had higher above ground biomass and NTTP was the lowest. Crop growth rate (CGR) was higher at PI-BT stage in TP either CT or NT but it was higher at PI-HD in DS. Net assimilation rate (NAR) was 15 and 24% higher in NTTP than CTTP at PI-BT and BT-HD, respectively, but CTTP had 15% higher NAR than NTTP at HD-12 DAH. In CTTP, higher leaf N concentration (2.04%) and uptake (5.9 g/m2) were observed at BT stage. In DS, N concentration and uptake were always higher in NT at all growth stages. It was found in the present study that CGR was closely related with LAD at BT-HD stage and grain yield was closely associated with leaf N (%) at HD stage. In DS either CT or NT had higher heat use efficiency (HUE) than TP as well as CT either TP or DS. Though DS had about 24% more number of panicles than TP but grain yield was higher in CTTP due to higher LAI, LAD, above ground biomass and bigger sink size (about 17% higher weight of panicle, higher number of spikelets per unit area and more number of grains per panicle) than DS.