The combining ability of popcorn S7 lines for Puccinia polysora resistance purposes

Abstract

The present study resulted from the lack of information on the genotypic expression ruling the resistance to rust and on the main traits of economic importance to the herein addressed crop. The combining ability of 16 popcorn lines and hybrids was assessed in partial diallel cross in two representative locations in Rio de Janeiro State, Brazil, where forty simple hybrids were obtained. The experiments followed a completely randomized block design with four repetitions and were conducted under natural infestation conditions in order to test the southern rust severity in the entire plant (SSW) and in the leaf of the first ear (SFPE), as well as the morpho-agronomic traits of greater interest: grain yield (GY) and

Combined Dominance and Additive Gene Effects in Trait Inheritance of Drought-Stressed and Full Irrigated Popcorn

“…On the other hand, Silva et al [15] and Schwantes et al [20], studying the inheritance of this trait under well-watered conditions, diagnosed partial dominance effects. These partial dominance values are in better agreement with most diallel studies with popcorn, almost all of which reported an additive action for PE [13,16,17,19,20]. However, in an evaluation of the same trait by SSR mapping, Babu et al [34] found QTLs with both dominant and partially dominant gene action.…”

“…Studies on the genetic effects on trait inheritance of popcorn under full irrigation [13][14][15][16][17] and under biotic stress [18,19], and among these, those using Hayman's diallel analysis [15,20], showed that the gene action of popping expansion is additive while that of grain yield and related components is mostly non-additive. For popcorn in water-stressed environments, this information is not available.…”

Research Article Combining ability of popcorn lines for resistance to the fungus <i>Puccinia</i> <i>polysora</i> (Pucciniaceae)

“…Therefore, the additive gene effects were assumed as more important in the expression of these traits. According to Vieira et al (2011) and Mafra et al (2018), the additive effects are highly relevant in the expression of southern rust resistance. For PE, the existence of a greater expression of additive effects for the trait was confirmed (Cabral et al, 2016;Pereira and Amaral Junior, 2001).…”

“…For PE, the existence of a greater expression of additive effects for the trait was confirmed (Cabral et al, 2016;Pereira and Amaral Junior, 2001). According to Mafra et al (2018), the use of parents in intrapopulation breeding programs is the best alternative to obtain selection gains for PE. For the traits GY and PV, the non-additive effects were predominant and therefore, the heterosis effects should be taken into account to explore the hybrid vigor for the selection of superior genotypes.…”

“…The use of pathogen-resistant varieties has been indicated as one of the most efficient and economical control strategies (Colombo et al, 2014). However, the use of genetic resistance in popcorn, especially against P. polyssora, is still rare (Mafra et al, 2018). In this context, with a view to the introgression of leaf-disease resistance genes, the popcorn breeding program of the Northern Fluminense State University Darcy Ribeiro (UENF) has been working since 2013 to characterize the resistance of popcorn in the UENF genebank with regard to the complex of corn leaf and ear fungal diseases (Kurosawa et al, 2016;Schwantes et al, 2017;Kurosawa et al, 2018;Mafra et al, 2018), in order to breed improved hybrids.…”