摘要:
以耐密抗倒性不同的品种(稀植大穗品种JK 518和JK 519、耐密抗倒品种XY335和CS 1;中等耐密品种ND 108)为材料,设5个密度处理,研究玉米茎秆的穿刺强度(RPS)的变化特点及其对群体种植密度的响应。结果表明玉米茎秆穿刺强度随生育期递进而增强,不同耐密性品种间随种植密度变化有较大差异。茎秆基部节间的穿刺强度随群体密度增加呈线性递减。茎秆节间RPS随着节位的上升而呈二次函数递减;不同耐密性品种间RPS以抽雄-吐丝期差异明显,以穗位以下节间,尤其第3~6节间表现差异较大。玉米抽雄前茎壁增厚早、茎皮较厚,则RPS高;吐丝期茎秆基部节间充实良好、穗位以下节间较短的群体,有利于提高品种茎秆抗倒伏能力。因此,以玉米抽雄前7 d至吐丝期、基部第3~6节间作为茎秆抗倒鉴定的关键时期和敏感部位,能够客观评价植株的抗倒伏能力,有效提高抗倒品种筛选效率。
关键词:
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作物
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应力分析
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茎秆
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玉米
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穿刺强度
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抗倒伏
Abstract:
Enhancement of biomechanical stalk strength is a key pathway to improve lodging resistance in modern maize (Zea mays L.) production. Four maize varieties were used to investigate the effects of planting density on stalk penetration strength as well as agronomic traits of maize stalk. The four maize varieties were differing in lodging resistance, i. e. JK 518 and JK 519 (low density-tolerance and lodging resistant), CS 1 (high density-tolerance and lodging resistant) and ND 108 (moderate density-tolerance). Five levels of density treatment were imposed, 3.00, 5.25, 7.50, 9.25, and 12.00×104 plants/hm2, respectively). The results indicated that the stalk rind penetration strength (RPS) was enhanced with growing of maize. There was difference of stalk RPS in years, and planting densities, respectively, between maize varieties differing in density-tolerance. With the rising of internodes position, stalk RPS were decreased significantly, which fitted a quadratic function curve (y = a + bx + cx2). Furthermore, the difference of stalk RPS between varieties differing in density-tolerance was present at internodes below ear, particularly at 3rd to 6th, in the tasselling–silking stag. With increasing planting densities, stalk RPS of base internodes decreased linearly significantly. Therefore, in the pre-tasselling stage, developed early and thicken in stalk wall indicates that stalk RPS was higher. In the silking stage, both shorter internodes below ear and well developed stalk base had the benefit for improving the stalk lodging resistance. In conclusion, that the 7 days before tasselling–silking stag and 3rd to 6th of the base internodes can be used as the suitable test time and sensitive internodes of the stalk of rind penetration strength in lodging resistance identification. This method can evaluate the stalk strength objectively and improve the breeding efficiency of selection varieties with lodging resistance.