高原气候下西藏不同熟期甘蓝型春油菜光温资源利用效率比较分析

为了充分协调产量潜力与气候资源高效利用的关系，研究高原气候下不同熟期甘蓝型春油菜的光温利用效率，选用3个不同熟期甘蓝型春油菜品系，设置4个播期，分析不同播期下西藏甘蓝型春油菜的生长发育及产量形成规律。结果表明：随着播期的推迟，参试油菜生育期间的温度升高，达到有效积温的天数较少，参试油菜生育期缩短；其中苗期、蕾薹期和花期较早播呈缩短趋势，角果成熟期有延长趋势。晚播油菜的茎秆伸长期雨热充足，参试油菜的株高较早播有增加，而茎粗有降低；晚播造成参试油菜前期营养生长不足，成熟期干物质积累较早播下降。晚播油菜生育后期遇持续降雨造成成熟期油菜的有效分枝数、单株有效角果数和单株粒重的降低，较早播油菜明显减产。播期改变了参试油菜的光、温利用效率，早熟品系NY16在B2播期（2021年3月15日）下光、温利用效率较高，分别为0.081 g·MJ^-1和1.017 kg·hm^-2·℃^-1；中熟品系NY28和晚熟品系NY52均在B1播期（2021年3月8日）下光、温利用效率较高，分别为0.1 g·MJ^-1 、1.282 kg·hm^-2·℃^-1和0.134 g·MJ^-1、1.712 kg·hm^-2·℃^-1。同一播期下中晚熟品系的光、温利用效率大于早熟品系。因此，适时早播可促进甘蓝型春油菜光温利用效率的提高，促进产量形成，早熟品系在3月15-22日，中晚熟品系在3月8-15日播种适宜。西藏一年一熟种植制度下，为充分协调生态条件与生产潜力关系，一定无霜期范围内，中晚熟品系的选育和利用可有效提高甘蓝型春油菜产量。

Comparative analysis on light-temperature resource use efficiency of spring rapeseed（Brassica napus） differing in maturity in China Tibet under plateau climate

In order to fully coordinate the relationship between yield potential and efficient utilization of climate resources, and investigate the light and temperature utilization efficiency of spring rapeseed under plateau climate in Tibet, 3 spring rapeseed （Brassica napus L.） lines （with different maturity） were selected as materials, and 4 sowing dates were set in field experiments. The lines were analyzed on growth and yield formation under different sowing dates. Results showed that, with the delay of sowing date, the temperature during rapeseed growth period increased, thus it took fewer periods to reach the effective accumulated temperature. Meanwhile, growth period of the lines was shortened, among which seedling stage, bolting stage and flowering stage were also earlier, resulting to a prolonged silique maturation period. Under the late sowing treatment, plants （at stem extension period） encountered more sufficient rainfall and more heat than those of early sowing, thus the plant height increased, and the stem diameter decreased. At the same time, late sowing resulted in insufficient vegetative growth in the early growth stage, and dry matter accumulation in mature stage was less than those of early sowing. Under the late sowing treatment, plants （at mature stage） encountered continuous rainfall which caused the reduction of branch number, silique number and seed weight, as a result, seed yield was significantly lower than that of early sowing. Sowing date changed the light-temperature utilization efficiency of the rapeseed. Early maturing line NY16 had higher light-temperature utilization efficiency at B2 sowing date （March 15, 2021）, as 0.081 g·MJ^-1 and 1.017 kg·hm^-2·℃^-1 respectively. The light-temperature utilization efficiency of medium maturing line NY28 and late maturing line NY52 were higher at B1 sowing date （March 8, 2021）, as 0.1 g·MJ^-1, 1.282 kg·hm^-2·℃^-1, 0.134 g·MJ^-1 and 1.712 kg·hm^-2·℃^-1, respectively. Under the same sowing date, the light-temperature utilization efficiency of medium- and late-maturing lines was higher than that of early-maturing lines. Therefore, timely （and early） sowing could improve the light-temperature utilization efficiency and promote rapeseed yield. Suitable sowing date was from March 15 to March 22 for early-maturing rapeseed, and March 8 to March 15 for medium- and late-maturing lines. Moreover, for the single-cropping system in Tibet, medium- and late-maturing rapeseed breeding might improve the yield of spring rapeseed.