EFFECT OF FORAGE CLIPPING ON GRAIN YIELD AND ASSOCIATED TRAITS OF WINTER WHEAT IN NORTHERN PAKISTAN

Winter wheat (Triticum aestivum L.) has the potential to be used as a dual purpose crop for forage-plus-grain production in the Northern regions of the North West Frontier Province (NWFP) of Pakistan. A set of 28 elite lines obtained from the winter wheat breeding program at Oklahoma State University (USA) were evaluated in a randomized complete block design with factorial treatment (unclipped and clipped) arrangements at Abbottabad, NWFP during 2005-06 crop season. Analysis of variance revealed significant genetic variation (P 0.01) among genotypes for plant height, spike length, spikelets spike-1, spike weight, biological yield and grain yield, while non-significant for green forage production and days to maturity. Moreover, highly significant differences (P 0.01) were observed among the unclipped and clipped treatments for all plant traits of winter wheat genotypes. Genotype×clipping interaction was highly significant (P 0.01) for plant height, spike length and grain yield, significant (P 0.05) for spikelets spike-1 and non-significant (P 0.05) for days to maturity, spike weight and biological yield. Means of 28 winter wheat lines for days to maturity, plant height, spike length, spikelets spike-1, spike weight, biological yield and grain yield under the unclipped and clipped treatments averaged 169.6 vs 173.0 days, 103.9 vs 89.5 cm, 11.2 vs 9.8 cm, 19.5 vs 18.2, 2.4 vs 1.5 g, 9056 vs 4386 kg ha-1 and 2725 vs 1393 kg ha-1, respectively. Maximum grain yield producing genotypes under the unclipped treatment were 05F504 (3750 kg ha-1) and 05F587 (3292 kg ha-1), while under clipped treatment genotypes 05F587 (2500 kg ha-1) and 05F515 (2229 kg ha-1), respectively. The apparent reduction in yield and yield contributing traits can be reduced to an acceptable level by using better crop management and input practices