INTERPLANT AND INTRAPLANT COMPETITION EFFECTS ON MAIN STEM YIELD OF THREE DIVERSE-TILLERING SPRING WHEATS

Abstract

Three spring wheat (Triticum aestivum L.) genotypes (Neepawa, Siete Cerros and M1417) were subjected to four levels of tiller removal (MS remaining, MS + T1 remaining, MS + T1 + T2 remaining, control) at three plant densities (two, four and eight plants per 15-cm-diameter pot) in a controlled environment to assess the effects of interplant and intraplant competition on stem dimensions and yield-related traits of genotypes with diverse tillering habits. Both types of competition resulted in reduced kernel weight and main stem grain yield and increased yield per pot. Interplant competition also reduced harvest indices while intraplant competition reduced main stem length and main stem diameter. The oligoculm genotype, M1417, was more sensitive to interplant competition than Siete Cerros and Neepawa. The increased sensitivity of M1417 appears to result from plant mortality combined with the inability to maintain kernel mass under severe interplant competition.Key words: Triticum aestivum, wheat (spring), tiller removal, grain yield, plant competition.