The objective of this study was to test if the response to 10 cycles of a recurrent selection program conducted under conventional tillage and rain fed conditions was the same when contrasted, for several traits, under conventional and non-tillage practices. During two season (2011 and 2012) the 44 S-derived families (four/C 0 to C 10 populations) were evaluated under conventional and non-tillage systems in two fields next to each other. Days to anthesis, plant height, grain, and biomass yield and 1000-grain weight were determined. The grain number per m 2 and harvest index was also estimated. From a random sample of 10 tillers the spikelet per spike and grains per spike were measured. For each trait, a linear mixed model (regression) was fitted to the experimental data. The slopes, under conventional tillage, were significant greater than zero for grain yield, harvest index, seeds per square meter, spikelet per spike and seeds per spike. Under non-tillage the list of traits showing slopes significantly greater than zero was shorter. For most traits there was a significant difference in the intercept terms between conventional tillage and non-tillage, which is interpreted as the tillage-practice effect. The concurrent evaluation in conventional and non-tillage soil managements of ten cycles of a recurrent selection program performed under conventional tillage confirmed the occurrence of a significant genetic progress only under conventional tillage.
The objective of the present investigation was to examine the relationships between agronomical behavior and grain quality along ten cycles of a recurrent selection program performed under rainfed condition. Twenty-four lines, four for each one of the 0, 2, 4, 6, 8 and 10 cycles of recurrent selection, were evaluated for two consecutive years (2011 and 2012). The experimental lines were evaluated under conventional (CT) and no tillage (NT) systems. Grain yield and grain weight were determined and harvest index and grain number estimated. Flour protein content, sodium dodecyl sulphate sedimentation (IS-SDS) and lactic acid SRC (LASRC) were considered as end-use quality predictive tests. The Spearman correlation coefficient was used to measure the relationships among yield, its components and grain quality parameters. Within the context of CT, flour protein content was negatively associated with all the agronomic variables. The IS-SDS has a negative association with the grain weight; meanwhile, LASRC associated positively with all the agronomic variables. When wheat was grown in NT, the relationship between IS-SDS and harvest index, like LASRC with all agronomic traits, was positive. Confining the discussion to the CT results, after ten cycles of recurrent selection the highest grain yield achieved was accompanied by a decrease in protein percentage. However, the decrease in the percentage of protein in more advanced selection cycles was offset by an improvement of its quality.
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