Combining abilities and inbreeding depression in commercial maize hybrids

Abstract

The objective of this study was to evaluate the combining ability and inbreeding depression of commercial maize hybrids for agricultural traits. Twenty-two commercial maize hybrids, 96 F 1 crosses from a partial diallel scheme, 22 S 1 populations and 4 controls were evaluated in a 12x12 simples square lattice experimental setup, totaling 144 treatments, in the municipality of Sabáudia (PR), Brazil, for harvests from 2011/2012 and 2012/2013. Three traits were evaluated: grain yield, plant height and ear height. The Griffing method (1956) was applied for the evaluation of the general combining ability (GCA) and specific combining ability (SCA). The 30B39, 30K64 and 30B30 hybrids showed increased yield, 30F53 and P1630 showed reduced plant height and AG9040 and AG7010 showed reduced ear height. These hybrids can be recommended for the extraction of inbred lines and formation of composites followed by intrapopulation selection. The combinations 30B39 x AG8088, 30B39 x AG9045 and P1630 x AG8021 showed desirable SCA effects for grain yield, plant height and ear height and are recommended for use in reciprocal recurrent selection programs. High magnitudes of inbreeding depression were verified for yield and lower values for inbreeding depression for plant and ear heights. Thus, strategies are recommended for interpopulation breeding accompanied by inbred lines extraction.

Inbreeding depression in maize populations and its effects on the obtention of promising inbred lines

“…Garbuglio et al (2009), studying the genetic variability in these same populations with different sets of S 1 families (and a different number of families), also found results of inbreeding depression below 20% for PH. Similar results were verified by Senhorinho et al (2015) when studying the effects of inbreeding depression in 22 commercial hybrids. In a work with popcorn carried out by Scapim et al (2006), the researchers showed a predominance of additive effect and an inbreeding depression of 10% for plant height and ear height.…”

Genetic divergence among processing tomato hybrids and formation of new segregating populations

“…Breeding programs whose objective is to obtain superior hybrids chose to use germplasm with a narrow genetic base for the formation of their base population [Hallauer, Carena and Miranda Filho (2010), Oliboni et al (2013), Souza Neto et al (2015 and Senhorinho et al (2015)]; studies report that commercial single cross hybrids have been used by breeders of outcrossed plants for the formation of segregating populations and is due to the advanced breeding process that these genotypes already utilize. Similarly, this can be an important strategy to generate base populations of autogamous plants such as tomato.…”