Study of yield loss and its mechanisms caused by grain shattering habit of crops.

落粒习性是植物的基本性状之一，野生植物的落粒习性对种子传播具有重要作用，而粮食作物的落粒习性则会造成收获前的产量损失。近年来，在日本，大豆和荞麦的种植面积在由水稻转化为旱地的高地不断增加，但由于在收获阶段的谷粒破碎，这些作物的产量损失严重。因此，本研究从栽培者的田间表现入手，探讨了不同品种、不同生长条件下的产量损失机理，结果表明，不同品种、不同年份、不同地点的落粒性造成的产量损失不同，造成产量损失的主要原因有多种。例如，大豆田由于与水稻等其他作物的收获过程竞争而失去了足够的收获时间，导致20%至30%的粮食产量下降，而超过50%的粮食产量下降。 ...更多信息 荞麦的产量因台风而减少了10%。收获前受台风影响而脱落的籽粒可作为下一次耕作的种子，并通过翻耕除草。荞麦的落粒性主要是由于花梗较细造成的，花梗直径与籽粒大小具有遗传相关性，因此，重粒型品种比小粒型品种对落粒有抗性。由于荞麦籽粒成熟期品质变化剧烈，建议早收，以改变籽粒品质，防止破碎造成的严重损失。在大豆上，未观察到籽粒落粒性与其它形态性状之间的明确关系。但种植户反映，由于田间生育期的差异，使他们难以确定收获期，而对收获期的错误判断导致产量和品质的下降。同一地块内的生长阶段差异主要是由土壤条件、路灯照明等因素造成的。对大豆生育期差异的空间分析表明，大豆生育期差异在田间是随机发生的，随着大豆的成熟，生育期差异逐渐减小。路灯光质对大豆植株生长的影响主要是由于日照短造成的，而蓝绿光和卤素灯对大豆植株生长的延迟影响较小。少

Grain shattering habit is one of elemental traits on plants because of the importance on wild plants for the seed dispersal, but on grain crops it causes the yield loss before harvest. Recently, the cultivation area of soybean and buckwheat is increasing in the upland filed converted from paddy in Japan, but these crops are suggested to show severe yield loss caused by the grain shattering habit at the harvesting stage. Thus, current study demonstrated the yield loss at the grower's field, and the mechanisms of the yield loss were investigated on the variation of cultivars, and the growing conditions.In this study, the amount of yield loss caused by the shattering habit was various among cultivars, years and locations, and severe damage on yield was observed by several reasons. For example, 20 to 30% of grain yield was dropped in soybean field because growers lose the adequate harvesting time due to the competition with the harvest process of other crop such as rice, and more than 50% … More of grain yield of buckwheat was blown off by typhoon. The grains shed by typhoon before harvesting was available as the seed for the next cultivation under weed control by plowing. The grain shattering habit of buckwheat was caused from thin pedicels, and the diameter of pedicel was genetically correlated with the size of seed grain, thus the cultivars of heavy grain type showed resistance on the shattering compared to the cultivars of small grain type. To prevent from severe loss by shattering, the early harvesting on buckwheat was suggested to change the grain quality, because the grain quality was drastically changed at the grain ripening period. On soybean, the clear relationship between the grain shattering habit and other morphological traits was not observed. However, growers suggested that the difference of the growth stage in a field embarrassed them to decide the harvesting time, and the misjudgment of harvesting time caused the decrease of the yield and the grain quality. The difference of the growth stage in a filed was caused by several reasons such as the variation of soil conditions, and the illumination of streetlight. The spatial analysis on the difference of the growth stage in a filed demonstrated the difference of growth stage occurred randomly in the field and became small gradually as soybean maturated. The light quality of a streetlight influenced the plant growth of soybean due to the short day plant, but blue-green light and halogen lump showed smaller effect on the delay of plant growth. Less