北方大豆种质引种南方后种子皱缩的研究

STUDY ON SHRIVELED SEEDS OF SOYBEAN DEVELOPED IN NORTHERN & GROWN IN SOUTHERN AREA

利用６个大豆种质研究不同水分散失速度下，由亚热带－热带高温所致皱缩型大豆种子表现的差异，通过本次研究及以往的观察，我们发现原产北方地区的大豆种质，在黄淮大豆生态区及其以南种植，普遍产生皱缩型种子而失去活力，因而在黄淮以南很难保存原产上述地区的大豆种质，限制了对大豆优良基因源的开发和利用。通常情况下，品种间的皱缩粒率有很大差异，变幅在７．４６％－８８．６８％之间，若在生理成熟期加快水分散失速度，则这一变幅为１０．２９％－９３．２７％，而在生理成熟期后期减缓水分损失速度，这一比率可降至０．５７％－８７．１％。即加快水分散失可使大豆种子皱缩趋于严重，而减缓水分散失则可有效降低皱缩型种子的比率。虽然植株的水分散失速度与土壤水分、大气温度和湿度以及品种本身有关，在鼓粒饱满、叶片转黄前后进行植株收获、风干，即可有效减缓植株的失水速度，从而显著降低皱缩型种子比率，在高温干旱条件下明显改善原产冷凉地区大豆种子的活力。

Six soybean varieties, of which five have the origin of high atitude and cool region of Heilongjiang, China, were introduced to the investigation to observe their performance of tropical/subtropical condition induced shriveled seeds uneler different water loss rates. From the study and other former obesrvations, we find that it is common for soybean varieties developed in high latitude and cool areas, if planted in tropical or subtropical areas, to yield a large number of shriveled seeds. These seeds are extremely weak in germination and emergence abilities. Therefore, it is very difficult to introduce soybean varieties from high latitude/cool regions to tropical/subtropical regions for both production and germplasm purposes. There is very significant variation of ratios of shriveled seeds among varieties ranging from 7.46 to 88.68% under normal water loss rate, 10.29 to 93.27% under accelerated water loss rate and 0.57 to 87.1% under slowed water loss rate. Accelerated water loss rate can obviously increase the number of shriveled seed of most soybean vareties, and slowed water loss rate can effectively decrease shriveled seeds. When combined with adequate sowing time, slowed water loss rate can reduce shriveled seed rate from as high as 76.67 to as low as 10.58%. lt was concluded that water loss rate, influenced by soil moisture, atmosphere humidity and variation of water holding ability among varieties, was the most important and direct factor that results in the formation of shriveled soybean seeds, and tropical/ subtropical varieties might have stronger ability of water holding than those of varities developed in high latitude/cool areas.