杂交中稻秧苗密度与苗质关系的研究

试验结果表明：杂交中稻秧苗密度对苗质的影响随秧龄玲延长而大。旱、湿秧小苗＜6400株／m^2苗高干重、叶面积等无显著差别；中、大苗苗高干重（y1)、单株分蘖数（y2)等与密度呈极显著负相关。其回归关系分别可以y1=a-bx和y2=ae^-bx式表达。式中a,b值随苗龄加大，同龄旱秧比湿秧b值小。苗质开始显著下降的秧苗密度（株/m^2）：中、大苗依次约为4000和2000（旱秧）；3000和1000（湿秧）。大苗单本栽，苗质显著较差的，大田生育及产量亦显著较差。高产高效的适宜秧苗密度（株/m^2)，小苗可达6500；中、大苗依次为3000和1000（旱秧），2000和400（湿秧）。

Study on the Relationship between Seedling Densityand Quality of Hybrid Middle Rice

Experimental results showed that the positive effect of seedling density on seedling quality was enhaneed with the increasing of seedling age.No apparent effect was observed on height,dry weight,and leaf area of dry and/or wet raised seedlings.However,significantly negative correlation was obtained between height and dry weight (y 1) of medium and big seedling,tillers of single seedling (y 2) and seedling density (x) with regression eguations was:y 1=a-bx,and y 2=ae -bx ,a and b in the equations rose with the increasing of seedling age;b value in dry raised seedlings was lower than that in the case of wet.The seedling quality began to decrease at the density (plant/m 2) of about 4000 and 2000 for medium and big seedlings (dry raised),respectively;3000 and 1000 for those wed raised ones.The suitable density (plant/m 2) for super efficiency and higher yield was suggested to be about 6400 for smaller seedlings,3000 and 1000 for dry raised medium and big seedlings,respectively;2000 and 4000 for wet raised ones.