播期对川中丘区玉米干物质积累与产量的影响

以川中丘区主推玉米品种‘正红505’和‘成单30’为材料,15 d为间隔,从3月26日至5月25日设置5个播期,研究播期对川中丘区玉米干物质积累与产量的影响,以期为本区域玉米的适期播种提供理论依据。结果表明,随播期推迟,玉米的生育期尤其是播种到吐丝期缩短,吐丝后干物质积累量及其对产量的贡献减少,收获指数降低;早播有利于增加花后干物质积累,晚播的产量形成需要更多地调运花前积累的光合产物;‘正红505’的产量随播期推迟而降低,‘成单30’的产量随播期推迟先略升高后降低,早夏播(5月10日播种)与春播(4月10日)玉米产量差异不显著,但夏播(5月25日播种)与‘正红505’一样因生育期缩短、干物质积累减少、收获指数降低而较春播显著减产;早春播‘正红505’产量较‘成单30’高,夏播‘成单30’产量高于‘正红505’,表明‘成单30’耐夏播能力较‘正红505’强。播期对‘正红505’干物质积累和产量及其构成因素的影响程度较‘成单30’大,生产上更应注意适期播种。该地区春播适宜的播期相对较宽,生产上应解决耕作制度与机械化生产的矛盾;夏播应注重耐夏播品种的选择,并争取在5月中上旬完成播种。

Effect of sowing date on dry matter accumulation and yield of maize in hilly regions of Sichuan Province, China

The main maize varieties ('Zhenghong 505'and'Chengdan 30') were sowed at 5 dates with 15-day intervals from March 26th to May 25th in hilly regions of Central Sichuan Basin to investigate the effects of different sowing dates on the dry matter accumulation and yield of maize.The study also aimed at providing the theoretical basis for the selection of appropriate sowing date of maize in the hilly regions of Central Sichuan Basin.The results showed that with delayed sowing date,the growth period (especially the period from seeding to spinning) shortened,dry matter accumulation and its contribution to yield decreased after spinning and harvest index decreased.However,early sowing increased dry matter accumulation after flowering.Yield formation in late sowing needed more allocation and transport of accumulated photosynthate before flowering.The yield of'Zhenghong 505'maize variety decreased with delayed sowing date,while,the yield of'Chengdan30'slightly increased firstly and then decreasing with delayed sowing.There was no significant reduction in yield of early summer maize 'Chengdan30'sown on May 10 and spring maize sown on April 10.However,compared with spring maize,yield of summer 'Chengdan30'maize sown on May 25 decreased due to shortened growth period,low dry matter accumulation and low harvest index.For early spring sowing,yield of'Zhenghong 505'maize variety was generally higher than that of'Chengdan 30'maize variety.For summer maize,however,yield of'Chengdan 30'maize variety was higher than that of'Zhenghong 505'maize variety.This suggested that'Chengdan 30'maize variety had a stronger vigor under summer sowing than'Zhenghong 505'maize.Sowing date had greater effect on dry matter accumulation,yield and yield components of'Zhenghong 505'maize than on'Chengdan 30'maize.This indicated that a close attention should be paid to sowing date in maize cultivation.In the hilly regions of Central Sichuan Basin,the suitable sowing date range of spring maize was relatively wide,implying that the production obstacle was rather the contradiction between farming system and mechanized production.More attention should be paid to summer sowing in terms of selection of crop variety and sowing date,which should end by mid-April or early May.