Componentes genéticos en poblaciones heteróticamente contrastantes de maíz de origen tropical y subtropical.

Abstract

A diallelic crossbetween 16 tropical and subtropical populations was formedat Iguala, Gro., in the winter nursery 2002 - 2003. Crossesand parents were evaluated during the 2003 growing seasonat INIFAP Bajio Experimental Station, in Celaya, Gto,Mexico. The objective was to identify the best populations tosupport the heterotic structure in our breeding program and assources to derived new inbred lines. Data were analyzedusing the Gardner and Eberhart model, in which variancecomponents can be separated to estimate additive and nonadditivegenetic effects. Results showed that despite theheterotic response involved in the formation of thepopulations, the “tropical x subtropical” heterotic pattern wasexpressed in specific combinations such PABG T x Sint “B”IG and Sint PABG I ACG x Sint “A” IG, with grain yields of12.5 and 12.4 t/ha respectively. These crosses presentedmaximum values of specific heterosis which can be used fordeveloping high-yielding hybrids through reciprocalrecurrent selection. Tropical population Sint “A” IGpresented the highest varietal effect, and because of its goodadaptation in the subtropic is considered an outstandinggermplasm to be incorporated in the Bajio Maize BreedingProgram. The best value of varietal heterosis, which is anindicator of General Combining Ability, was observed inPABG I GH “A” synthetic which can be used as tester. Moredetailed analysis will permit to take advantage of thegermplasm involved to benefit maize breeding programs.