The distributions of tuber sizes in droughted and irrigated crops of potato. I. Observations on the effect of water stress on graded yields from differing cultivars

Summary The distributions of the yield and of the numbers of tubers were examined in graded samples of tubers from field experiments designed to compare droughted and irrigated crops of cultivars of potato thought to differ in their tolerance of drought. Drought caused a downward shift of about 7–10 mm in the centres of both distributions. The consequences were that smaller fractions of lower total yields reached the sizes usually specified for table (40–80 mm) and crisping (<45 mm) potatoes. Differences in the distributions of numbers of tubers in droughted and irrigated crops were statistically significant in four of the six cultivars examined. The main reason for lower ware yields in the droughted crops was that fewer tubers reached the minimum size (40 mm). The effect of delayed harvest was to shift the distributions upwards.     

绿竹林丰产结构研究

对不同年龄组成的绿竹丛产笋量对比、丛立竹数和该丛当年笋产量的回归关系、以及绿竹丛立竹数 ( N)与丛冠幅 ( CW)的回归分析 ,结果表明 ,不同年龄组成的绿竹丛平均单株产笋量差异显著 ,由 1、 2年生竹组成的绿竹丛平均单株产笋分别比由 1～ 3年生竹组成的绿竹丛和 1～ 4年生竹组成的绿竹丛多 0 .1 638kg和 0 .1 979kg.丛立竹数为 4～ 7(株 /丛 )的绿竹林 ,在相应最大密度下可获得最大笋产量 (笋产量大于 4650 kg/hm2 ) .研究结果提出了绿竹林丰产结构指标 ,可为绿竹丰产培育提供指导     

人工促进栽培措施对小佛肚竹秆形变异的影响研究

小佛肚竹(Bambusa ventricosa McClure)隶属箣竹属(Bambusa)箣竹亚属(Subgen.Bambusa),合轴丛生型,为我国著名的观赏竹种,自然分布于福建、广东、广西,现全国各地乃至世界多国有引种[1],具两种秆形--畸形秆和正常秆,畸形秆常用于植物盆景制作和庭院观赏栽培.     

肥密互作对寒地水稻源库关系的影响

采用多元二次旋转回归正交组合设计试验，研究3个施期(基肥和蘖肥、穗肥、粒肥)的氮肥用量、调节肥施用时间及穴距等5个因素对粳稻垦鉴稻10号源库关系的影响。结果表明，基肥和蘖肥用氮量与最大叶面积指数及单位面积结实颖花数呈显著正相关；调节肥施用时间与单位面积结实颖花数呈负相关；穴距与最大叶面积指数及单位面积结实颖花数呈极显著二次曲线关系。说明通过适当加大前期用氮量或协调前期用氮量与种植密度等栽培措施的互作，可在适当范围内(即基、蘖肥用氮量达到140 kg/hm2，穗肥，粒肥用氮量为0 kg/hm2, 调节肥施用时期6.7叶，穴距12 cm)提高群体结实颖花数并最终提高产量。     

不同刺孔次数和数量对香菇 生殖生长的影响

系统比较了不同刺孔次数和数量对香菇生殖生长的影响，结果表明，各处理间存在明显差异，以栽培袋在发菌过程中进行三次刺孔，分别在接种后菌丝圈相连时进行第一次刺孔，刺孔数量为4个；菌丝长过半边时进行第二次刺孔，刺孔数量为8个，每面4个；两次刺孔规格均为孔径2 mm，深度15 mm；在菌袋长满菌丝并有部分瘤状物凸起时进行第三次刺孔，刺孔数量为80个，深度为50 mm，孔径5 mm为最佳。