Combinig ability for grain yield of late maize lines

N. Petrovska
Abstract. The present study shows the results from testing experimental hybrids for grain yield which were obtained by the partial diallele system by Savchenko (1966, 1978) in 2004. General combining ability (GCA) and specific combining ability (SCA) of 10 late inbred maize lines which belong to two genetically different groups (Lancaster and Reid) were evaluated. The hybrids received from them were tested both in 2005 and 2006 on the fields of the Maize Research Institute, Knezha, under conditions without irrigation and plant density 40000 plant/ha. The aim of the study is to analyze both CA for grain yield and the genetic parameters of newly created late inbred maize lines in terms of their more consistent use in selection. As a result of the experimental work, three inbred lines with high GCA are pointed out (ХМ 4582, КС 4607 (Lancaster) and ХМ 4583 and FХМ 4658 (Reid)). Since GCA is determined by additively acting genes, these lines may be used as testers for evaluation of GCA of new source materials in the earlier stages of the selection process. The SCA of inbred lines ХМ 4647, ХМ 4582, КС 4682 and FХМ 4658 is high and they are suitable for direct heterosis selection and creation of high yielding hybrids as in the inheritance of their genetic parameters mostly dominant and epistatic gene effects are displayed. After the results were analyzed, some specific recommendations for the inclusion of these inbred lines in different selection programs were made. In addition, as a direct outcome of the experimental work, four high yielding hybrids were pointed out and they are still being tested in varietal and ecological trials.