The Development and Survival of Fruit in Relation with Plant Structure of Field-grown Cotton

Abstract

Fruiting pattern and fruit survival of Thai cotton cultivar SSR 60 were investigated during a rainy season trial and two dry-season trials. During the dry-season one trial was managed with the aim of achieving limited plant growth. Plant structure, fruit production and survival were mapped at 2-days intervals. Initiation of first square was delayed by poor plant growth but time between first square and first flower together with boll period of first fruit were mainly temperature dependent. A comprehensive description of fruit phenology and change in plant structure was achieved by plotting the vertical progression of square-appearance, flowering and boll opening of each fruiting position according to time. In each trial, linear models fitted well to the data. Fruits located on P1 fruiting sites displayed a better survival than fruits located on other sites. Despite this difference frequency distribution of shedding with fruit age highlighted the existence of two similar critical stages whatever fruit position considered. The description of fruiting pattern proposed, combined with a monitoring of fruit survival should help understanding differences in fruit number and production in agronomic treatment and farmers’ fields.