根蘗型苜蓿的引种和育种Ⅰ.根蘖型苜蓿的引种研究

INTRODUCTION AND BREEDING OF ALFALFA WITH ROOT TILLER PARTI: STUDY ON INTRODUCTION OF ALFALFA WITH ROOT TILLER

本文对引进的九个根蘖型苜蓿品种的生育期、形态特征、根系特点作了观测。其根系可分为主根型、侧根型、水平根型和根蘖型四大类。根蘖的显著特点是有水平侧根,根上有根蘖膨大部,其中有芽或幼枝形成。Spreador、Rangelander、Roamer、Rambler、Drylander、Kane六品种根蘖明显,根蘖株率在20～40％之间;一般每株有水平根14～24条,集中分布在7～20厘米土层内,根蘖节分布在各级水平根上或根的交叉处。植株扩展面积最大的是Rambler苜蓿。生长第三年孕蕾期的冠幅最大可达3.4m^2,为普通苜蓿的2～6倍。根蘖的表现与土壤类型等因素有关。

The root systems of nine varieties of alfalfa with root tiller which were introduced can be classfied main root, side root, level root and root tiller. The characteristic of root tiller is that it has level side roots with inflated part, on which buds and sprouts are formed. The root tiller of Spreador, Roamer, Pambler, Drylander and Kane is obvious. The percentage of the plant with root tiller is between 20～24%. The number of level root in each plant is 14 to 16,which concentrated distribution in 7～20cm soil layer. The root tiller nodes appear on the level root or cross area of roots. Ramber plant expands most greatly, the largest crown canopy can reach 3.4m^2 during the third year of growth phase,which is 2 to 6 times as large as that of common alfalfa. The performance of root tiller is related to the factors of soil type and so on.