Valentin Ivanov KOSEV (BULGARIA)
Abstract. A small–plot field trial was carried out from 2007 to 2009 including seven field pea (Pisum sativum L.) cultivars from the Ukraine and Bulgaria. The ecological stability in tested pea cultivars was determined in relation to seed yield. Stability parameters were determined by regression analysis according to methods by Eberhart and Russell and Tai. The analysis of variance proved that influence of factors genotype, environment and genotype x environment and seed yield had a very high level of probability. The cultivars Kerpo from Bulgaria and Usatii 90 from Ukraine could be considered close to an ideal type (bi=1.04, λi=11.08; bi=1.05, λi= 1.12), suitable for growing in different environments. On the other hand, the Bulgarian Mir (bi=1.56, λi=49.41) and Ukrainian Harkovskii Etalon (bi=1.28, λi=95.88) were identified as unstable (bi>1), but with good response that provide them with high seed yields in certain environments. The cultivars Vesela (bi=0.77, λi=6.77) from Bulgaria, Pleven 10 (bi=0.71, λi=59.49) from Bulgaria and Rezonator (bi=0.68, λi=35.07) from Ukraine were assessed as stable (bi<1), but with a low adaptability except for Vesela. In conclusion, cultivars Kerpo, Usatii 90 and Vesela may be regarded as suitable for including in future hybridisation programmes and developing novel field pea lines with high and stable seed yields in contrasting environments.
Key words: adaptability, breeding, pea, seed yield, stability