论文部分内容阅读
白兰瓜引入兰州近40年来,随着生态环境与农业结构的变化,品种本身也有不少变异。首先是栽培面积增加,群体不断扩大,在没有严密的良种繁育制度下,造成种性混杂,引起品种退化;其次是病害滋生,特别是自1972年以来病毒病的猖獗危害,不仅使亩产大幅度下降(1975年全市平均亩产只有565斤),品质也显著变劣,含糖量降至10％以下,严重地影响了白兰瓜的生产发展,全市播种面积由近1万亩,降至3000余亩;第三
Introduction of white melon in Lanzhou nearly 40 years, with the ecological environment and the changes in agricultural structure, there are many varieties of variation. The first is the increase of cultivated area and the continuous expansion of the population. In the absence of strict thoroughbred breeding system, this causes mixed species and leads to the degeneration of cultivars. Secondly, the breeding of diseases, especially the rampant damage of virus diseases since 1972, (1975, the city average yield of only 565 pounds), the quality is also significantly worse, the sugar content dropped below 10%, seriously affected the production of white melon growth, the city sown area of nearly 10,000 mu, down to More than 3,000 acres; the third