优良柚类引种评比试验

从南方7省引进的30个优良柚类品种（品系类型）在常德市进行评比试验，依据1991～1994年连续4年的产量，按照“经济林优良品种、类型选择标准”，超过参试均值30％以上、高于对照值50％以上者评为优良品种，评选出沙田柚和溪蜜柚2个适合本地发展的优良品种，其果实主要经济性状的遗体力分别在66．25％和62．19％以上，产量的遗传力分别为57．08％和53．24％，遗传增益分别为29．82％和32．31％。

Variety Test on Low Temperature-resistant Pleurotus ostreatus Strains in Beijing Area

With 7 familiar Pleurotus ostreatus strains in Beijing region as the test materials,the randomized block design method was adopted to analyze the antagonistic effects,mycelial growth rate,yield of mushroom at low temperature season,total biological efficiency and agronomic characteristics of fruit bodies.The results showed that there were antagonistic effects and differences in all the tested items between all the tested strains,of which the strain PL5 had the shortest spawn age,the strain PL3 showed the highest total biological efficiency,and the fructification of the strain PL7 tasted crisp and tender.