Development of Indeterminate Growth Habit of Soybean variety Chiang Mai 3

Abstract

The objective of experiment was to determine the development and growth stages of soybean variety Chiang Mai 3. The experiment was conducted at Chiang Mai Field Crops Research Centre in both dry and wet seasons in 2000 and 2001. The results in dry season showed that soybean stem had developed to V 17 - V 20 and the growth habitat was indeterminate from the 1455^th nodes. The beginning of first flower, was bloomed at 38 days after emergence in R 1 stage and was overlapped with V 7. The interval of flowering was 29- 35 days and peak of flowering was 13-15 days after the first flower which was being bloomed with the average 8.4-9.5 flowers/ plant/2 days. Total flowers had 71.3 flowers/ plant. Pod setted 59.2 % and to R 8 at 62 days after the first flower bloomed or 100 day after emergence. In this growth stage, R 8 was optimum to harvest for seed by then soybean seed had 15.6% of seed moisture content with the highest seed germination and the seed vigour. In wet season, soybean stem had 18-25 nodes and the growth habitat was indeterminate from the 1655^th nodes. The beginning of first flower was bloomed at 32 days after emergence and was overlapped with V 10. The interval of flowering was 23-29 days and peak of flowering was 7-9 days after the first flower which was being bloomed at the average of 23.5-25.0 flowers/ plant/2 days. Total flowers had 116.6 flowers/ plant. Pod setted 61.2 % and to R 8 at 52-60 days after R 1. At R 8 soybean Seed had 16.3- 23.3 % of seed moisture content and had the highest seed germination but the highest seed vigour was 56 days after R 1 or 88 days after emergence. Therefore, the optimum harvested period for the highest seed quality was 52-56 days after R 1.