Inheritance of Expansion Volume and Yield in Two Popcorn ✕ Dent Corn Crosses

Abstract

Improvement of expansion volume, defined as the volume of popped corn per gram of unpopped corn, generally is considered the most important objective of popcorn (Zea mays L.) breeding programs. Popcorn, however, generally is inferior to dent corn with respect to yield and other agronomic characteristics. Detailed information on the inheritance of expansion volume and grain yield in popcorn ✕ dent corn crosses was not available in the literature. The objective of this study was to determine the inheritance of expansion volume and grain yield, including yield components, in two popcorn ✕ dent corn crosses. Generation means analysis was used to quantify genetic effects in the popcorn ✕ dent crosses Ia53 ✕ B73 and Ia28 ✕ Mo17. Significant additive genetic effects were detected for ail traits in both crosses. Significant dominance genetic effects were detected for expansion volume in the cross Ia28 ✕ Mo17, and for grain yield, ear length, ear diameter, and 5O‐kernel weight in both crosses. Dominance effects resulted in reduced expansion volume, and increased grain yield, ear length, ear diameter, and 5O‐kernel weight. Significant epistatic effects for grain yield were detected in the crosses Ia53 ✕ B73. Expansion volume was negatively correlated with all yield components except for number of kernel rows. Thus, relative to other yield components studied, selection for high kernel row number would appear to result in the least reduction of expansion volume. Results from this study indicate that breeding methodologies which exploit additive genetic variation assoicated with expansion volume and dominance variation associated with grain yield are most likely to result in concurrent improvement of these two traits.

Inbreeding depression and genetic components for popping expansion and other traits in Brazilian populations of popcorn

“…The additive gene effects were higher than the dominant effects (Tables 2 and 3) in several studies that have shown the predominance of additive genetic effects in the control of popping expansion (Dofing et al, 1991;Larish and Brewbaker, 1999). Therefore, pop-VOLUME 37 nº3 SEPTEMBER -DECEMBER 2010 α µ+ : additive effects; δˆ: dominance effect; PH: plant height (m); EH: ear height (m); PI: prolificacy index; P100: hundred-kernel-weight (g); GY: grain yield (kg ha -1 ); PE: popping expansion (mL g -1 ).…”

“…The main feature of quality popcorn is its popping expansion volume (Mora and Scapim, 2007;Pereira et al, 2008), and there is evidence of the predominance of additive genetic variation for this trait (Dofing et al, 1991;Larish and Brewbaker, 1999;Miranda et al, 2008). Four quantitative trait loci (QTLs) on chromosomes 1S, 3S, 5S and 5L were found to explain 45% of the phenotypic variation in popping expansion (Lu et al, 2003).…”

Correlação entre heterose e divergência genética estimadas por cruzamentos dialélicos e marcadores moleculares rapd em populações de milho-pipoca

“…Em fato explica os resultados nas combinações, cujas essas populações não contribuíram para o aumento da CE. Na população ZL, com o maior valor demonstrado para CE, ocorreu um dos menores valores de g i para PG, o que era previsto, em virtude da existência de correlação negativa entre essas características (VERMA e SINGH 1979;DOFING et al, 1991;SILVA et al, 1993;ANDRADE, 1995;SAWAZAKI, 1996;SIMON, 2000;PIPOLO et al, 2002).…”

Predição de ganhos genéticos por índices de seleção na população de milho pipoca UNB-2U sob seleção recorrente

“…Em milho-pipoca, a correlação negativa entre as duas principais características de valor econômico -capacidade de expansão e produtividade de grãos -dificulta a seleção de genótipos de interesse para o melhoramento (LIMA et al, 1973;ZINSLY e MACHADO, 1987;DOFING et al, 1991;DAROS et al, 2004a) e torna necessário o emprego de procedimentos genético-estatísticos que permitam minimizar ou, mesmo, tornar inócuos os efeitos deletérios da resposta correlacionada. Para tanto, os índices de seleção são procedimentos indispensáveis, pois permitem obter ganhos simultâneos mesmo para características com efeitos adversos, que podem ter origem na ligação gênica ou na pleiotropia.…”