Evaluation of picking time and vertical distribution of bolls effects on some seed germination and vigor traits and seedling field emergence of cotton (Gossypium hirsutum L.) Sahel cultivar

In order to evaluate of picking time and vertical distribution of bolls effects on some seed germination and vigor traits and seedling field emergence of cotton (Gossypium hirsutum L.) Sahel cultivar, two experiments were conducted in Golestan province during 2011-2012 in farm and a laboratory phases. In first, farm phases were carried out in factorial experiment based on a complete block design (RCBD) with four replications and two factors. Factors levels was boll picking time (first and second picking) and vertical distribution of bolls (lower, middle and upper parts). Germination and vigor tests was surveyed on these seeds and in second farm study, same seeds was planted under first year farm experiment procedure in order to evaluating of seedling filed emergence percentage, main root length of seedling and seedling vigor index under field condition. Analysis of variance of the first year of the study showed that picking time and vertical distribution of boll had only significant effect on the percent of seed germination but their interaction effect on germinated seed percentage after accelerated ageing test, seed electrical conductivity, germination percent in cool germination test, germination percent in warm germination test and cool warm vigor index were significant. Mean comparison of studied traits indicated that seed volume and seed bulk density of first picking bolls in compare to second picking bolls had effectively more values and seed germination percentage of first picking and middle-located bolls promoted the highest germination percentage. Evaluating of the seed vigor tests results under factors interaction (picking time × vertical distribution of bolls) revealed in accelerated ageing test, the seeds of lower and middle bolls had better germination percentage in compare to other treatments. Results of seedling filed emergence percentage under filed circumstance was indicated that seeds of middle bolls had highest seedling filed emergence percentage but there was no significant different between lower and upper boll seeds on seedling root length size. The highest correlation among germinated seed percentage under field condition was seen with cool germination results. Outcomes of this study were indicated in order to produce high quality seed germination and seed vigor of cotton Sahel cultivar, seed can be removed in first picking and middle bolls