Root growth of green pea (Pisum sativum L.) genotypes

Root development of 12 genotypes of green pea was followed using a minirhiz otron system. Rooting-depth development followed a simple pattern, consisti ng of an initial lag phase during germination and early growth, followed by a linear phase that ended approximate to 10 d after the onset of flowering . All genotypes followed this general pattern. Significant differences were found in the length of the linear phase of rooting-depth development. Thes e differences were due to variation in the length of the initial lag phase, and variation in the time until the onset of flowering. The genotypes dth the lowest seed weight also showed the longest lag phase. No significant di fferences in the rate of roofing-depth development during the linear growth phase were found among the genotypes. The rate of rooting-depth developmen t was estimated to be 0.086 cm d(-1)degrees C-1 across the genotypes. Measu rements on six of the genotypes in root-observation boxes showed the same d ifferences between genotypes as found in the field, although the rate of ro oting depth development was much higher. The observed differences in rootin g depth and the fact that these differences could also be observed in a sim ple way in the root-observation boxes, suggest that efficient breeding meth ods for rooting-depth development can be developed.