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"Fandango": long term adaptation of exotic germplasm to a Portuguese on-farm-conservation and breeding project

2009; Experimental Institute for Cereal Growing; Volume: 54; Linguagem: Inglês

2279-8013

P. M. M. Mendes-Moreira, María Carlota Vaz Patto, Maria Teresa da Silva Mota, João Pedro Carvalho Moreira, João Pedro Santos, Joselito Santos, E. Andrade, Arnel R. Hallauer, Silas E. Pêgo,

Crop Yield and Soil Fertility

Climatic change emphasize the importance of biodiversity maintenance, suggesting that germplasm adapted to organic, low input, or conventional conditions is needed to face future demands. This study presents: I - The two steps genesis of the synthetic maize popula- tion 'Fandango'. A) 'NUTICA' creation: in 1975, Miguel Mota and Silas Pego, initiated a new type of polycross method involving 77 yellow elite inbred lines (dent and flint; 20% Portuguese and 80% North American germplasm) from the NUMI programme (NUcleo de mel- horamento de MIlho, Braga, Portugal). These inbreds were intermated in natural isolation and progenies sub- mitted to intensive selection for both parents during con- tinued cycles; B) From 'NUTICA' to 'Fandango': 'Fandan- go' was composed of all the crosses that resulted from a North Carolina Design 1 matting design (1 male crossed with 5 females) applied to 'NUTICA'. II - The diversity evolution of 'Fandango' under a Partici- patory Breeding project at the Portuguese Sousa Valley re- gion (VASO) initiated in 1985 by Pego, with CIMMYT sup- port. Morphological, fasciation expression, and yield trials were conducted in Portugal (3 locations, 3 years) and in the USA (4 locations, 1 year) using seeds obtained from five to seven cycles of mass selection (MS). The selection across cycles was done by the breeder (until cycle 5) and farmer (before cycle 11 till present). ANOVA and regres- sion analysis on the rate of direct response to selection were performed when the assumption of normality was positively confirmed. Otherwise the non parametric Multi- variate Adaptive Regression Splines (MARS) was per- formed. Response to mass selection in Iowa showed significant decrease in yield, while in Portugal a significant increase for time of silking, plant and ear height, ear diameters 2, 3, 4, kernel number, cob diameters, and rachis was ob- served. At this location also a significant decrease was ob- served for thousand kernel weight and ear length. These results showed that mass selection were not effective for significant yield increase, except when considered Lousa- da with breeder selection (3.09% of gain per cycle per year). Some non-parametric methods (MARS, decision trees and random forests) were used to get insights on the causes that explain yield in Fandango. Kernel weight and ear weight were the most important traits, although row numbers, number of kernels per row, ear length, and ear diameter were also of some importance influencing 'Fandango' yield.