排序方式: 共有15条查询结果,搜索用时 217 毫秒
11.
罗大刚 《西南科技大学学报(哲学社会科学版)》1994,(1)
对玉米双苗的概念、双苗的自然发生频率、形态分类及其遗传规律进行了初步研究,对各类双苗在作物育种或栽培上的应用进行了探讨。 相似文献
12.
Xiaojie Xu 《Journal of applied statistics》2017,44(14):2593-2620
Using daily prices from 496 corn cash markets for July 2006–February 2011, this study investigates short-run forecast performance of 31 individual and 10 composite models for each market at horizons of 5, 10, and 30 days. Over the performance evaluation period September 2010–February 2011, two composite models are optimal across horizons for different markets based on the mean-squared error. For around half of the markets at the horizon of 5 days and most of them at 10 and 30 days, the mean-squared error of a market's optimal model is significantly different from those of at least other 23 models evaluated for it. Root-mean-squared error reductions through switching from non-optimal models to the optimal are generally around 0.40%, 0.55%, and 0.87% at horizons of 5, 10, and 30 days. 相似文献
13.
14.
本次试验利用增重和产奶两个试验分析说明微贮秸杆在养牛业中的应用前景,进而探索利用、转化秸杆的新途径,促进养牛业经济效益的进一步提高。 相似文献
15.
选育高产优质的玉米新品种,优化粮饲结构,是当今玉米育种的重要课题。提高选育高产预见性的基本经验是:配对亲本要具有“三差”和“三强”特点。“三差”即光敏性差异,籽粒差异、株叶型差异;“三强”即抗主要病害强、抗倒力强、长果穗遗传力强。优质品种的选育主要利用含优质蛋白质和高油基因及选用粗蛋白质高的材料。选育方法上探索了与内部品质相关的简易目测为主的方法,即系统筛选籽粒成熟时胚乳油浸色深、种胚较大鼠喜食者,辅以必要化验分析。 相似文献