Estimativas de parâmetros de heterose em híbridos de populações F2 de milho

Abstract

Os híbridos desenvolvidos com o uso eficiente da heterose contribuem significativamente para o aumento de produtividade, na cultura do milho. O presente trabalho teve por objetivos avaliar híbridos de populações F2, quanto aos caracteres agronômicos, e estimar parâmetros genéticos das populações F2, bem como a heterose, utilizando-se o método de Gardner & Eberhart. Verificaram-se maiores estimativas de efeito de populações F2, para massa de grãos, na Pop.9, Pop.11, Pop.14 e Pop.15, sendo estas indicadas para programas de seleção recorrente intrapopulacional e obtenção de linhagens superiores. A Pop.10 e Pop.16 destacaram-se pelos maiores efeitos de heterose de parentais, para massa de grãos. Os híbridos Pop.12 x Pop.10 e Pop.13 x Pop.10 apresentaram alta produtividade e efeitos elevados de heterose específica, indicando a existência de locos em dominância, no controle genético de massa de grãos.

<b>Genetic parameter estimates and identification of superior white maize populations

“…The GY trait showed significance in the heterosis parental effects (h i ), which reveals the existence of variation in the contribution of each parent to the performance of the hybrid, indicating dispersion of allele frequencies in the population (Oliveira et al, 2004). Similar h i results for GY were found by other authors and enabled the selection of the best parents and their respective hybrids (Tonette & Carena, 2014;Bernini & Paterniani, 2012;Doná et al, 2011;Silva & Miranda Filho, 2003;Scapim et al, 2002).…”

“…Moreover, diallel crosses are used to analyze the genetic design, providing estimates of useful parameters that allow for the selection of the best genitors to obtain hybrids, and to understand the genetic effects of a trait (Gonçalves et al, 2014;Melani & Carena 2005;Cruz, Regazzi, & Carneiro, 2004). This method has been used to evaluate several agronomic traits in hybrids obtained from common maize populations (Tonette & Carena, 2014;Bernini, & Paterniani, 2012;Doná, Paterniani, Gallo, & Duarte, 2011) and in specialty corns, such as popcorn (Cabral et al, 2015;Solalinde et al, 2014) and sweet corn (Assunção et al, 2010;Rodrigues et al, 2009), allowing the identification of the best parents and their hybrid combinations for the evaluated traits. Cruz et al (2004) reported several types of diallel analysis, such as balanced, partial, circulating, incomplete and unbalanced, highlighting that the most applicable type was the balanced diallel proposed by Hayman (1954), Griffing (1956) and Gardner and Eberhart (1966).…”

“…According to Bernini and Paterniani (2012), this method is superior to the others when open pollinated varieties are crossed, since it provides useful genetic information to the breeder from the mean values of the population and not from the variances.…”

Association of secondary traits with yield in maize F 1 's

“…It is up to the breeder to assess the magnitude of the significance and quantify the effects of the interaction and thus determine the techniques and strategies in the adoption of the selection procedures. Understanding the associations between characters is important for genetic gains and selection of the best parents, whose breeding objective is the development of high performance hybrids (HALLAUER, 2007;2010;BERNINI & PATERNIANI, 2012).…”

Estimates of heterosisparameters in elephant grass (Pennisetumpurpureum Schumach.) for bioenergy production

“…According to Bernini and Paterniani (2012), the more productive hybrids have positive and high specific heterosis, while the less productive ones have negative and (Table 7). Hybrids H8, H17 and H18 showed outstanding effects of ŝ ij for the DMY trait also in the rainy season cuts (Table 6).…”