Please use this identifier to cite or link to this item:
Title: Combining ability for resistance to soybean rust in F2 and F3 soybean populations
Authors: Maphosa, M. .
Talwana, H.
Tukamuhabwa, P
Gibson, P
Keywords: IGlycine max
Soybean rust resistance
Phakopsora pachyrhizi
Additive gene effects
Issue Date: Feb- 2
Publisher: Field Crops Research, Elsevier
Abstract: The impact of soybean rust (Phakopsorapachyrhizi) on soybean yields has been extensively studied. How¬ever, few studies have evaluated early generation segregating material under field conditions for soybean rust resistance to facilitate selection. The objective of this study was to estimate combining abilities for soybean rust resistance in the F2 and F3 populations at MUARIK and F3 populations simultaneously across five locations. Combining ability for soybean rust resistance was estimated from a half diallel cross of eight soybean using disease severity and sporulation rates as indices for resistance. A consistent contribution of additive gene action was observed at MUARIK across F2 and F3 despite high environment contribution to both severity and sporulation rate. The simultaneous evaluation of F3 populations in five diverse loca¬tions produced similar results with significant GCA effects for both traits. There were, however, greater genotypic effects to soybean rust severity and sporulation across the five test environments, although genetic systems of severity and sporulation rate acted independently. Additive and additive x additive epistatic gene effects were the most common form of GCA controlling resistance. Specific combining ability did not always contribute to soybean rust resistance. The positive correlation between parental severity, sporulation rate performance and GCA estimates suggested that selection of parents for soybean rust resistance breeding can be based on parental performance. Parental line UG 5 was the most outstand¬ing producing the greatest number of resistant populations. This study underscores the importance of additive gene effects in the control of soybean rust severity and sporulation rate.
Appears in Collections:Department of Crop and Soil Science

Files in This Item:
File Description SizeFormat 
MAPHOSA, M.pdf411.58 kBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.