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941.
942.
依据Griffing方法配制种植不同类型的复合双列杂交组合,分别设水、旱二种水分条件。在不同生育时期测定株高、株穗数、株粒重、穗粒数、黄叶片数、SOD、POD、MDA等农艺、生理生化性状,研究不同组合类型对杂交后代的遗传力影响及其与抗旱性的关系及遗传规律。结果表明,可采用抗旱指数(DRI)作为评价小麦品种抗旱性强弱的指标。旱地株粒重、旱地穗下节长、旱地黄叶片、籽粒饱满度、落黄、旱地成穗数、旱地株高等7个质量性状和数量性状与抗旱性关系密切且遗传力较强,可作为高产种质杂种后代的早期抗旱性鉴定指标。SOD活性和MDA含量由于广义遗传力和狭义遗传力均较高,可以在杂种后代早期世代进行选择,OA能力和POD活性广义遗传力较高但狭义遗传力低,适宜在杂种后代的晚期世代进行选择。 相似文献
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侧柏种源试验苗期的初步研究 总被引:7,自引:3,他引:4
石文玉 《北京林业大学学报》1986,8(1):74-83
在北京的3个不同海拔高度,对来自31个地区的侧柏种子进行了种源试验。对一年生苗的分析表明,种源间差异显著。一年生苗生长快的种源比生长慢的高3.6倍。通过根系调查及苗高生长量与地表温度和土壤含水量的相关分析,可以看出天然林子代比人工林子代的适应性强。初步研究结果可为北京地区选择适宜的侧柏种源和侧柏的种源区划提供参考。 相似文献
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Bulked Segregant Analysis to Detect QTL Related to Heat Tolerance in Rice (Oryza sativa L.) Using SSR Markers 总被引:3,自引:0,他引:3
ZHANG Gui-lian CHEN Li-yun XIAO Guo-ying XIAO Ying-hui CHEN Xin-bo ZHANG Shun-tang 《中国农业科学(英文版)》2009,8(4):482-487
The study was undertaken to assess the genetic effect of quantitative trait loci (QTLs) conferring heat tolerance at flowering stage in rice. A population consisting of 279 F2 individuals from the cross between 996, a heat tolerant cultivar and 4628, a heat-sensitive cultivar, was analyzed for their segregation pattern of the difference of seed set rate under optimal temperature condition and high temperature condition. The difference of seed set rate under optimal temperature condition and high temperature condition showed normal distribution, indicating the polygenic control over the trait. To identify main effect of QTL for heat tolerance, the parents were surveyed with 200 primer pairs of simple sequence repeats (SSR). The parental survey revealed 30% polymorphism between parents. In order to detect the main QTL association with heat tolerance, a strategy of combining the DNA pooling from selected segregants and genotyping was adopted. The association of putative markers identified based on DNA pooling from selected segregants was established by single marker analysis (SMA). The results of SMA revealed that SSR markers, RM3735 on chromosome 4 and RM3586 on chromosome 3 showed significant association with heat tolerance respectively, accounted for 17 and 3% of the total variation respectively. The heat tolerance during flowering stage in rice was controlled by multiple gene. The SSR markers, RM3735 on chromosome 4 and RM3586 on chromosome 3 showed significant association with heat tolerance respectively, accounted for 17 and 3% of the total variation respectively. The two genetic loci, especially for RM3735 on chromosome 4, can be used in marker-assistant-selected method in heat tolerance breeding in rice. 相似文献
949.
Integrated pest management in field vegetable crops in northern Europe — with focus on two key pests
Improvements in (1) insecticide application, (2) supervised control, and (3) pest forecasting systems have each helped to reduce considerably the amounts of insecticides required to control fly, caterpillar and aphid infestations in vegetable crops in northern Europe. By growing plants that are partially resistant to certain major pests, it is now possible to apply even less insecticide than the dose recommended for the crop. In crops where only small amounts of insecticides are applied, natural predators should prevent large increases in pest insect populations and natural parasitoids should reduce the numbers of pest insects entering subsequent generations. The possible impact of introducing transgenic plants and the use of physical (crop covers), cultural (crop rotation, undersowing) and microbial (e.g. fungi, bacteria and nematodes) methods of control are also discussed. The withdrawal of certain insecticides, as a result of environmental and commercial pressures, means that some crops may soon be without appropriate insecticides for controlling one or more of the major pest species. Whether such systems will be sustainable, remains to be seen. 相似文献
950.