Influence of micro-environment on the growth characteristics of cotton (Gossypium hirsutum L.) with reference to row positions

Abstract

This experiment was conducted at Grdarasha Experimental Field, University of Salaheddin, Erbil (36.11 o N, 44.01 o E), to study the growth performance of cotton cultivar Coker 310 under four micro environmental conditions. The levels were composed of row directions and sowing dates as main plot (E1-E4) in split plot of Randomized Complete Block Design (RCBD). A total of 13 row positions (RP1-RP13) of different central and outer positions were included in sub plots, those rows had dual roles, as a principle constitute of the sub-plot and as a bilateral use to check the reality of the sampling statistic concept that suggests not to depend on the samples from terminal parts. with three replicates, during two successive growing seasons in 2021 and2022. Results showed that the highest value was recorded from (E1and E2) for both seasons. The highest values were recorded of weight dry matter from (E3 and E4), leaf area from (E3), leaf area index from (E3 and E4), crop growth rate and relative growth rate from (E4 and E1) at 60 DAS f or both seasons. at 90 DAS the highest values of weight dry matter, leaf area, crop growth rate was recorded form (E4) and leaf area index from (E3) in the first season, while the second season at 90DAS the highest values of weight dry matter, leaf area, leaf area index, crop growth rate was recorded from (E3) and relative growth rate was recorded from (E4). The row positions (RP8 and RP5) superiority in plant height for both yeas. (RP1 and RP9) recorded superiority in weight dry matter, (RP1 and RP8) recorded superiority in leaf area, (RP2 and RP8) recorded superiority in leaf area index and (RP10 and RP3) in relative growth rate at 60DAS for both years. The highest values at 90DAS of weight dry matter, leaf area and leaf area index were recorded from (RP9 and RP10) for both years. The highest values of crop growth rate were recorded from (RP9 and RP11) at 60 and 90 DAS for both years. The highest value of relative growth rate at 90DAS was recorded from (RP12)