Study on Optimum Block Size and Shape in Uniformity Trial of Sunflower (Helianthus annuus)

A uniformity trial for the determination of optimum size and shape of blocks was conducted at CCS Haryana Agricultural University research farm, Hisar, Haryana from February 2014 to June 2014 on sunflower hybrid 66A507 Pioneer, on a field of size 35 m × 40 m, which reduced to 32 m × 36 m after eliminating border effects. The crops of each basic unit (1 m × 1 m) were separately harvested and the contiguous plots grouped into blocks of 4, 8, 12 and 16 plots. The blocks elongated in the N-S direction were more effective in reducing error variation than those elongated in the E-W direction. The coefficient of variation decreased from 14.88 to 7.30 with increase in block size from 4 to 16 for plot size 1 m2, thus larger blocks were found to be more efficient (R2 = 0.963 for 16-plot blocks) than smaller ones. The 16 size block was found to be more efficient with block shape of 16 m × 1 m, which should be recommended for further researches on sunflower crop in the particular area. In general, blocking arrangements were found to be more efficient than those without blocking.