Effect of leaf type and plant spacing on growth, yield and fiber properties of irrigated upland cotton (Gossypium hirsutum L.) in middle Awash

In irrigated cotton growing of Middle Awash, although several varieties were released and have been in large-scale production, the plant spacing recommendation was not variety specific and information in effect of planting configurations on growth, yield and fiber properties are scarce. Therefore, the objective of this study was to determine the effect of inter-row and intra-row spacing and their interactions on growth, yield and lint properties of normal and okra-leaf type cotton. Thus, a study was conducted at Werer Agricultural Research Center's experimental site, located 285 km east of Addis Ababa, on chromic vertisol (Silty clay to clay) with a pH ranging from 7.6 to 8.0. Treatment were factorial combinations of two leaf typesnormal and okra-leaves, three inter-row spacings (0.70 m, 0.90 m and 1.05 m) and three intra-row spacings (0.20 m, 0.30 m and 0.40m), and were laid in Randomized Complete Block Design (RCBD) with three replications. The normal-leaf type (Sille-91) was early with narrow intra-row (0.20 m) and further increase in intra row spacing delayed maturity while maturity of okra-leaf type was hastened because of increased intra-row spacing from 0.30 m to 0.40 m. Okra-leaf type attained significantly higher plant height and height to node ratio as compared to the normal-leaf type. Leaf area index increased significantly as intra-row reduced from 0.30 m to 0.20 m at both early flowering and cutout stages. Averaged over intra-row spacing, normal-leaf type produced higher above ground vegetative dry matter due to narrow inter-row 0.70 m (124 g square m -2) and decreased significantly with further increase inter-row spacing, of 0.90 m and 1.05 m but okra-leaf produced relatively higher above ground vegetative dry matter at the intermediate inter-row of 0.90 m (108.48 g square m -2). Normal-leaf type produced fewer flowers but retained a higher percent of bolls than okra-leaf type. Conversely, okra-leaf type produced significantly many flowers but only a small percentage of the resulting young bolls were retained. The okra-leaf type produced significantly large bolls as inter-row increased from 0.90 to 1.05 m inter-row spacings. Alternatively, normal-leaf type produced significantly lower boll weight irrespective of inter-row spacings. The normal-leaf type (Sille-91) produced 10% and 13%) advantage of higher seed cotton yield and lint yield and lint yield ha sup(-1) respectively as compared to the okra-leaf type (Tate). Interaction between narrow inter-row spacing (0.70 m) and intra-row (0.20 m) caused a relatively short 2.5% span length, bet further increased of intra-row spacing from 0.30 m to 0.40 m, increased 2.5% span length. It may be further noted that 2.5% span length of normal-leaf type is greater than that of okra-leaf type at all population density. Correlation results demonstrated a significant and positive association of lint yield with total dry matter (r=0.40), seed cotton yield (r=0.37) and span length 2.5% (p0.05