Influence of Soil Compaction and Drought on the Growth, Photosynthesis and Carbohydrates in Fugi/M.9EMLA Apple Plants

Greenhouse grown 1 year old potted M.9EMLA apple trees ( Malus pumila Borkh) were subjected to the soil compaction and, after growing under compacted or non compacted conditions for 6 weeks, were subjected to drought stress by withholding water for an additional six week period. Soil compaction and drought stress significantly reduced plant height, number of leaves, and leaf area. Although drought significantly inhibited photosynthesis and transpiration, compaction only depressed transpiration. Furthermore, the effects of drought on plant growth, photosynthesis and transpiration were much greater than the effects of compaction. The rate of water loss from compacted plants was lower than the rate from non compacted controls and this may explain the insignificant impact of compaction on photosynthesis. Sorbitol, glucose, and fructose concentrations increased over time during the drought stress period whereas sucrose concentration declined. In well watered controls, sucrose concentration was much higher in leaves of compacted plants than in the leaves on non compacted controls. For most of the sampling dates the leaf sorbitol concentration was lower in leaves on plants growing in compacted soil than in the leaves of those of the non compacted controls. Although interactions between the effects of compaction and drought were highly significant for plant growth variables during the onset of drought, interactive effects on photosynthesis, transpiration, relative water content and carbohydrate variables were inconsistent. Compaction and drought both have major effects on apple plants and the interactions between these two stresses are complex.

中国近30年苹果育种亲本选择与选配分析

通过对中国果树育种工作者育成的183个苹果品种亲本材料的分析,归纳总结出:选育以人工杂交常规育种为最常用的方法,所占比例为50.3%;亲本的来源以国外品种为主导,亲本配置组合“国外品种×国外品种”、“国外品种×国内品种”育成品种的比例分别是52.2%、21.7%,其它方法育成品种占26.1%;育成品种的亲本品种主要有‘金冠’、‘富士’、‘东光’、‘国光’、‘红星’、‘元帅’、‘金红’、‘M9’、‘惠’、‘寒富’,可以称之为骨干亲本,抗寒品种的亲本主要是以‘东光’、‘金红’和‘寒富’作母本,矮化砧木的亲本主要是以‘M9’作父本,鲜食品种亲本主要是‘金冠’、‘国光’、‘惠’和‘寒富’作母本和‘富士’、‘红星’、‘元帅’作父本,能更高效地选育出符合预期目标的苹果品种。上述分析结果为苹果目标育种和性状遗传研究等亲本材料选择提供参考依据。

SSR标记的开发在苹果遗传多样性中的应用

本试验从苹果(Malus pumila Mill)转录组数据库中挖掘SSR标记,发现其SSR标记类型共有六种,分别为:单核苷酸、二核苷酸、三核苷酸、四核苷酸、五核苷酸和六核苷酸,其中频率较高的重复类型为单核苷酸、二核苷酸和三核苷酸。从41 890条苹果无冗余转录组序列中共搜索到了1 803条至少含有1个SSR的序列,占转录组的4.30%。高频重复类型为单核苷酸、二核苷酸和三核苷酸,其中数量最多的是A/T,其次是AG/CT和GAG/CTC,共占SSRs的98.23%。该试验共设计了20对引物,分别对20份苹果材料进行PCR扩增。结果显示:20对引物均能扩增出条带,平均扩增条数为2.7。并对供试的20份苹果品种进行了聚类分析,结果与形态学及生物学分类基本一致,证明品种间亲缘关系的远近具有一定的规律,栽培品种与砧木品种的种间亲缘关系较远,而栽培种和砧木品种的种内亲缘关系较近。另外,本研究为杂交育种挑选合适的亲本,杂交育种以及培育作物新品种提供了一定的理论基础。