Direct Selection For Grain Yield Research Articles

D2 Analysis to Evaluate the Genetic Diversity of Peanut (Arachis hypogaea L.)

Background: A complex quantitative characteristic, yield is heavily impacted by the environment. The productivity of groundnuts can be increased less effectively through direct selection for grain yield. The study aimed to determine the genetic diversity. Methods: The Mahalanobis D2 statistic was used to quantify the genetic diversity among 24 genotypes of groundnut for seven quantitative and six qualitative criteria. Result: There is sufficient diversity among genotypes, as evidenced by the fact that all of the features in the ANOVA showed significance. High GCV and PCV values were seen for the traits primary-branches/plant (PB), secondary-branches/plant (SB), pod yield/plant (PY), sucrose content (SC), total free aminoacids (TFA), total soluble solids (TSS) and iron content (IC), demonstrating that these traits were well chosen. High heritability and genetic progress as a percentage of mean were observed for plant height, PB, SB, PY, Hundred-pod weight (100-PW), SC, TFA, TSS and IC, demonstrating additive gene-action is in charge of these traits. Twenty-four genotypes were divided into nine clusters using Tocher’s method of clustering, with cluster I being the biggest with sixteen genotypes. Cluster VII and Cluster IX had the greatest inter-cluster distance, which showed that their individuals were more diverse (26.91). In order to obtain transgressive segregants for yield and yield parameters, taking into consideration the cluster distances and cluster means in the current experiment, an emphasis should be focused on establishing crossings between genotypes from clusters VII and VIII that are promising.

Principal Component Analysis and Path Coefficient Analysis for Groundnut Yield and Seed Quality Attributes (Arachis hypogaea L.)

Background: A complex quantitative characteristic yield is heavily impacted by the environment. The productivity of groundnut can be increased less effectively through direct selection for grain yield. The current study aimed to study the variation among diverse groundnut genotypes. Methods: Phenotypic data was collected on seven quantitative and six qualitative characters for 24 genotypes under study carried out in randomised block design (RBD). GRAPES software has been used for analysis. Result: Analysis of variance revealed significant differences among the genotypes for all the characters indicating the prevalence of ample genetic variability within the genotypes. Significant positive associations were observed for primary branches, secondary branches, 100-pod weight, shelling per cent, protein and zinc content. Path analysis revealed that plant height, primary branches per plant, hundred pod weight, shelling percent, protein content and zinc content are the most important characters which could be used as selection criteria for effective improvement of pod yield. Using GRAPES software, Fourteen Principal components are extracted based on mean values of which the first five PCs showed 73.24% variation with eigen values more than 1. Biplot constructed by Principal component analysis revealed Hundred pod weight and hundred kernel weight as important traits for study.

Developing Novel Rice Genotypes Harboring Specific QTL Alleles Associated with High Grain Yield under Water Shortage Stress.

Rice is considered a strategic crop for many countries around the world, being the main cash crop for farmers. Water shortage stress occurrence as a result of climate change is among the main threats challenging rice breeders in the last few decades. In the current study, 19 Fn-lines were developed from four populations by crossing a reverse thermo-responsive genic male sterile (rTGMS) line, M.J.5460S, with the three high-quality Egyptian commercial cultivars Giza177, Sakha105, Sakha106 and the promising line GZ7768 as male parents. These newly developed lines, along with their parents, and two water shortage stress-tolerant international genotypes (Azucena and IRAT170), were cultivated under water-shortage stress conditions and compared with their performance under well-watered conditions. Results indicated that the yielding ability of the 19 newly developed lines exceeded those for the two Egyptian parents (Giza177 and Sakha105) under well-watered conditions. The lines M.J5460S/GIZA177-3 and M.J5460S/GIZA177-12 were the best performing genotypes under water shortage stress conditions. The genetic and heritability in broad sense estimates indicated that direct selection for grain yield (GY) under water-shortage stress is highly effective in the current study. Molecular marker analysis revealed that M.J5460S/GIZA177-3 had accumulated the quantitative trait loci (QTL)s, on the chromosomes 2, 3, and 9, which contribute to GY under water-shortage stress from their high yielding tolerant ancestor, M.J5460S. It could be concluded that those lines are high yielding under both well-watered and water-stress conditions harboring several QTLs for yield enhancement under both conditions and that the markers RM555, RM14551, RM3199, RM257, RM242, and RM410 are among the markers that could be used in marker-assisted selection (MAS) breeding programs for such stress condition.

WAASB‐based stability analysis and simultaneous selection for grain yield and early maturity in soybean

AbstractSoybean [Glycine max (L.) Merr.] is the leading Indian oilseed crop grown under rainfed conditions. Meticulous understanding of genotype × environment interaction patterns is essential to develop superior and widely adaptable soybean varieties. In the current study, 32 soybean genotypes were evaluated at eight locations for two consecutive years. Additive main effect and multiplicative interaction ANOVA revealed that only 41.6% of variance was explained by the first two interaction principal component axes (IPCAs), leaving 58.4% to the remaining 13 IPCs. The weighted average of absolute scores (WAASB) stability index, a best linear unbiased prediction–based mixed model that takes in to account all the IPCAs, has been used in stability analysis. SL1171 (WAASB score, 4.09) was found to be highly stable among the genotypes under study, with grain yield (2,050.87 kg ha−1) lower than the grand mean (2,082.50 kg ha−1). A superiority index that allows weighting between mean performance and stability (WAASBY) was used to select stable and high yielding genotypes. MACS 1620 (WAASBY score, 74.47) was found to be high yielding (2,476.05 kg ha−1) and widely adaptable. A simultaneous selection index (i.e., multi‐trait stability index [MTSI]) has been used for selecting early‐maturing and high‐yielding genotypes. DSb 33 was found to have the lowest MTSI (0.001) and can be used as a parent for breeding for early maturity and higher yield. The 100‐seed weight was found to be positively correlated with grain yield and can be used in direct selection for grain yield. Through genotypic cluster analysis, NRC 146 was found to be more divergent, with the highest mean 100 seed weight (16.39 g), and therefore can be used as a parent for breeding solely for grain yield.

Approaches for enhancing grain yield of finger millet (Eleusine coracana)

AbstractFinger millet is gaining importance as a food crop with the increasing emphasis on nutritional aspects and drought resilience. However, yield improvement has stagnated. Therefore, popular varieties have been examined for the purpose of whether direct selection for grain yield can be continued or an alternate trait-based approach using the germplasm is necessary. Direct selection for grain yield over the ruling variety, cv. GPU-28 (Germplasm Unit) has not been satisfactory. The path analysis has revealed a high direct effect of mean ear weight on grain yield followed by a moderate direct effect of photosynthetic rate and leaf area index. Furthermore, backward stepwise regression analysis revealed that among the independent traits, the mean ear weight made a significant contribution (60.8%) towards grain yield, followed by the photosynthetic rate (39.2%). The regression equation predicts the inclusion of mean ear weight by 1.0 g extra (as in GE-2672) to cv. GPU-28 will increase grain yield by 4.74%. The trait-specific genotypes are superior to the cv. GPU-28 were GPU-67 (photosynthetic rate) and GE-2672 (mean ear weight) and they could be used as donors for yield improvement. Future selection would aim for genotypes having 70–75 days for flowering with 4−5 productive tillers and mean ear weight of more than 8−9 g/ear. The possible approaches for enhancing grain yield are also discussed.

Quantitative characterization of proximate sensing canopy traits in the SoyNAM population

AbstractThe average increase of soybean [Glycine max (L.) Merr.] grain yield per year is not enough to meet the estimated need by 2050. Contributing factors may include narrowing genetic diversity in cultivated soybean germplasm arising from direct selection for grain yield and insufficient knowledge of the genetic influences on physiological traits associated with grain yield. Canopy development plays a critical role in the light intercepted by soybean crops throughout the growing season. Rapid canopy closure facilitates complete light interception and optimizes growth dynamics, ultimately increasing biomass accumulation and grain yield. This study sought to use ground‐based digital imagery as a phenotyping tool for quantitative characterization of seasonal canopy coverage and light interception in the genetically diverse Soybean Nested Association Mapping (SoyNAM) population. We took weekly measurements of canopy coverage from early vegetative to mid‐reproductive growth for 5,600 recombinant inbred lines during the 2013 and 2014 seasons. An asymptotic logistic growth curve fit to the coverage data allowed us to estimate daily changes in canopy coverage in the intervals between the sampling dates, enabling calculation of canopy dynamic parameters. These parameters included average canopy coverage, cumulative intercepted photosynthetically active radiation for the total sampling period, vegetative growth period, reproductive growth period, and the number of days required to reach 30, 50, and 70% canopy coverage. Variance component estimation showed that genetic differences among families significantly influenced variation in phenotypic expression for all canopy parameters. The narrow‐sense heritabilities for all canopy parameters were high (h2 = .81–.90), suggesting opportunities for genetic gains in canopy development through selection of superior genotypes.

Genetic gain for rice yield in rainfed environments in India.

The complexity of genotype × environment interactions under drought reduces heritability, which determines the effectiveness of selection for drought tolerance and development of drought tolerant varieties. Genetic progress measured through changes in yield performance over time is important in determining the efficiency of breeding programmes in which test cultivars are replaced each year on the assumption that the new cultivars will surpass the older cultivars. The goal of our study was to determine the annual rate of genetic gain for rice grain yield in a drought-prone rainfed system in a series of multi-environment trials conducted from 2005 to 2014 under the Drought Breeding Network of Indian sites in collaboration with the International Rice Research Institute (IRRI). Our results show a positive trend in grain yield with an annual genetic yield increase of about 0.68 % under irrigated control, 0.87 % under moderate reproductive stage drought stress and 1.9 % under severe reproductive stage drought stress due to breeding efforts. The study also demonstrates the effectiveness of direct selection for grain yield under both irrigated control as well as managed drought stress screening to improve yield in typical rainfed systems. IRRI's drought breeding programme has exhibited a significant positive trend in genetic gain for grain yield over the years under both drought stress as well as favorable irrigated control conditions. Several drought tolerant varieties released from the programme have outperformed the currently grown varieties under varied conditions in the rainfed environments on farmers' fields.

Efficiency of indirect selection for grain yield in maize (Zea mays L.) under low nitrogen conditions through secondary traits under low nitrogen and grain yield under optimum conditions

Small-scale maize farmers in sub-Saharan Africa use meager amounts of nitrogen (N) in their maize crops. N use efficient varieties can provide a solution to the problem of low N conditions through efficient N uptake and utilization. The objectives of this study were to i) compare the quantitative genetic parameters of grain yield and secondary traits under different nitrogen levels and ii) assess the efficiency of indirect selection for grain yield under low N stress through yield under optimum N and secondary traits under low N stress in maize. Doubled haploid lines derived from five bi-parental populations were evaluated. Genotype effect for grain yield and secondary traits was significant at all sites. Genetic variance for grain yield was reduced by 17% under moderate N stress and 63% under severe N stress conditions, while genetic variance for days to anthesis and plant height increased under both moderate and severe low N stress. The heritability of most secondary traits was consistently higher than that of grain yield. Correlations of grain yield with plant and ear heights were positive under low N conditions. Despite the reduction in genetic variances under low N conditions, there was genetic variability for grain yield and secondary traits. Direct selection for grain yield under low N rather than under optimum conditions was more efficient for yield improvement under the low N condition. The use of an index of secondary traits could increase the efficiency of improving grain yield rather than selection for only grain yield under low N conditions.

Direct and Indirect Selection for Grain Yield in Bread Wheat (Triticum aesitivum L.)

Direct and indirect selection for grain yield through 1000grain weight, spikelet fertility and spike density were achieved in bread wheat at the Exper. Farm Fac. Agric., Minia Univ. Egypt during the three successive seasons of 2016/17 to 2018/19. After two cycles of pedigree selection phenotypic variation of grain yield/plant, 1000grain weight, spikelet fertility and spike density decreased rapidly from F2 base population to F4. Indirect selection through high 1000 grain weight resulted in the highest grain yield/plant (23.62g) followed by direct selection for grain yield/plant (20.66 g). Average direct gain for the ten selected families of direct selection for grain yield showed highly significant increase in percentage of the bulk sample of 62.95% and the better parent of 39.25%. Pedigree selection was effective in detecting the high yielding families. Family No. 145 gave significant (P≤0.01) grain yield in percentage of the better parent and bulk sample by 77.09 and 107.23%, respectively. Average direct response in percentage of the bulk sample was significant and reached 21.08% for 1000 grain weight, 31.12% for spikelet fertility and 7.27% for spike density. Three families; No. 15, No. 72 and No. 153 surpassed significantly the bulk sample by 33.83, 43.01 and 29.28%, respectively, when selection practiced for 1000 grain weight. Family No. 145 considered to be a promising line in grain yield and spikelet fertility. High strong positive genotypic correlation was found between grain yield with each of weight of spikes/plant (0.81), no. of grains/spike(0.71), weight of grains/spike (0.91), 1000grain weight(0.92) and spikelet fertility(0.70).

A novel polymorphism in the 5′ UTR of HvDEP1 is associated with grain length and 1000-grain weight in barley (Hordeum vulgare)

The gene HvDEP1, on barley (Hordeum vulgare L.) chromosome 5H, encodes a γ-subunit of the heterotrimeric G-protein complex and was previously determined to be a candidate gene underlying a major quantitative trait locus for grain length. In the present study, we identified a 9 bp indel (insertion–deletion mutation) at position –84 bp from the start codon within a reported upstream open reading frame located in the 5′ UTR (untranslated region) and developed a diagnostic molecular marker. We also identified a 13 bp indel (–514 bp) in linkage disequilibrium that bridges an important regulatory motif. Using a doubled-haploid population and a barley diversity panel, we were able to show that the effects of these indels were environmentally stable and consistently delineated phenotypic groups based on grain length and 1000-grain weight. Genotypes represented by deletions at these two positions relative to the reference cv. Morex had consistently shorter grains, by 3.69–3.96%, and lower 1000-grain weight, by 2.38–4.21%, in a doubled-haploid population studied. Additionally, a diversity panel was tested but consistent differences were observed only for grain length, reinforcing literature indicating the importance of this gene for grain-length regulation. The frequency of the longer and heavier grained reference allele was higher in modern cultivars, suggesting that indirect selection for longer grain may have occurred through direct selection for grain yield via grain-weight improvement. These results indicate that grain length and 1000-grain weight in barley can be manipulated by targeting variation in gene promoters through marker-assisted selection.

Phenotypic correlation, path coefficient and multivariate analysis for yield and yield-associated traits in groundnut accessions

Yield is a complex quantitative trait largely influenced by the environment. Direct selection for grain yield is less efficient in improving groundnut productivity. The selection efficiency can be ...

English

The current study was conducted to assess the trait association and path analyses in thirty-six rain fed lowland rice genotypes at two locations. The aim of this present study was to estimate the extent of association between pairs of characters at phenotypic and genotypic levels and thereby compare the direct and indirect effects of the characters. The field experiment was laid out in 6x6 simple lattice design with two replications during 2015/16 cropping season. Thirteen characters were measured including yield and related traits. The extent of phenotypic correlation coefficient values indicated presence of fairly strong inherent association among the studied traits. Moreover, association analyses studies indicated yield had significantly (p<0.05) positive genotypic correlation with days to heading, days to maturity, filled grains per panicle, fertile tillers per plant harvest index, total spikelets per panicle and biomass yield. Path coefficient analyses revealed that biomass yield followed by harvest index, total spikelets per panicle and plant height exhibited the highest direct effects on grain yield; these traits can be considered for direct selection for grain yield of rice.   Key words: Direct effect, indirect effect, path analysis, ground combat vehicle (GCV), packed cell volume (PCV). &nbsp

Utilizing High‐Throughput Phenotypic Data for Improved Phenotypic Selection of Stress‐Adaptive Traits in Wheat

Efficient phenotyping methods are key to increasing genetic gain and precisely mapping genetic variation. Recent phenotyping developments have resulted in high‐throughput phenotyping platforms that utilize proximal sensing to simultaneously measure multiple physiological traits. However, there has been limited exploration of this high‐resolution, multiple phenotypic data. To address this, two wheat (Triticum aestivum L.) biparental populations were grown for 3 yr under two different treatments, drought and heat stress, at the International Maize and Wheat Improvement Center, Ciudad Obregon, Mexico. The lines were evaluated at multiple time points throughout the growing season with “Phenocart,” a portable field phenotyping platform that integrates precision GPS, spectral reflectance, and thermal sensors. Both normalized difference vegetation index (NDVI) and canopy temperature (CT) were correlated to final grain yield. We found that broad‐sense heritability (H2) and correlation to yield for both NDVI and CT had a regular pattern over the growing season. The maximum correlation and H2 existed during mid‐grain‐fill stage, while correlations were low for early‐ and late‐season measurements. We also found that the H2 of CT on a given day was a good indication of how well that dataset correlated to yield. In addition, the temporal NDVI data from heading to senescence was modeled to evaluate stay‐green and senescence differences between lines. Based on the repeatable correlations, high‐throughput phenotyping platforms can be used to assist with indirect selection through rapid collection of physiological measurements compared with direct selection for grain yield alone.

Correlation and path analysis of morpho-physiological and yield traits in <italic>boro</italic> rice (<italic>Oryza sativa</italic> L.)

Thirty rice genotypes of local and exotic origin were analyzed to ascertain the genotypic and phenotypic correlation among 21 morpho-physiological and yield traits and their direct/ indirect contribution to grain yield under <italic>boro</italic> season. The result revealed that grain yield per plant had significant positive correlation with biological yield (0.927**, 0.766**), harvest index (0.748**, 0.658**), days to first flowering (0.459*, 0.377*), panicle length (0.501**, 0.445*), grains per panicle (0.576**, 0.484**) and 1000 grain weight (0.573**, 0.460*) at both genotypic and phenotypic levels. Path coefficient analyses at both genotypic and phenotypic levels revealed high positive direct effect of biological yield (0.7181) and harvest index (0.6382) on grain yield per plant. Thus direct selection for grain yield per plant and indirect selection through these characters would be effective to improve yield in <italic>boro</italic> rice.

Correlation between agronomic and stem borer resistant traits in maize: Implications in selection

Objective : The interrelationship between agronomic and resistant traits of two stem borer species, and its influence on selection was studied in a yellow maize population, DMR ESR-Y, at Ibadan between 2009 and 2010. Methodology and results: Two hundred and fifty (250) full-sib progenies of the population with three checks were evaluated. Resistant traits had negative correlations with most agronomic traits including grain yield (GY). GY had significant relationship with days to 50% pollen shed, (DTA) (rg = 0.49**), plant height (PH) (rg = 0.46**) and ear aspect (EA) (rg = -0.98**). Indirect selection of GY via DTA and PH gave gains that were a little lower than direct selection for GY, but they have higher heritability. Indirect selection of stem tunnelling and cob damage through EA would give gains of 150.64 % and 106.94 % respectively. Conclusion and application of results : This result suggested that either days to 50% pollen shed or plant height could be considered in selection for stem borer resistance. Ear aspect is another good criterion to consider instead of cob damage and stem tunnelling to hasten selection. The result indicated that breeders selecting for stem borer resistance and high yield could consider plant height, days to 50% pollen shed, ear aspect and grain yield itself as criteria for selection. In selecting the best genotypes in any crop improvement study therefore, breeders need to consider not only the magnitude of the correlation between pairs of traits, but the desirability of their relationship, ease of measuring the traits, correlated response among the traits, and heritability of the secondary trait selected. Keywords : Correlated responses, heritability, secondary traits, selection, stem borer resistance

Breeding high-yielding drought-tolerant rice: genetic variations and conventional and molecular approaches.

The increased occurrence and severity of drought stress have led to a high yield decline in rice in recent years in drought-affected areas. Drought research at the International Rice Research Institute (IRRI) over the past decade has concentrated on direct selection for grain yield under drought. This approach has led to the successful development and release of 17 high-yielding drought-tolerant rice varieties in South Asia, Southeast Asia, and Africa. In addition to this, 14 quantitative trait loci (QTLs) showing a large effect against high-yielding drought-susceptible popular varieties were identified using grain yield as a selection criterion. Six of these (qDTY 1.1 , qDTY 2.2 , qDTY 3.1 , qDTY 3.2 , qDTY 6.1 , and qDTY 12.1 ) showed an effect against two or more high-yielding genetic backgrounds in both the lowland and upland ecosystem, indicating their usefulness in increasing the grain yield of rice under drought. The yield of popular rice varieties IR64 and Vandana has been successfully improved through a well-planned marker-assisted backcross breeding approach, and QTL introgression in several other popular varieties is in progress. The identification of large-effect QTLs for grain yield under drought and the higher yield increase under drought obtained through the use of these QTLs (which has not been reported in other cereals) indicate that rice, because of its continuous cultivation in two diverse ecosystems (upland, drought tolerant, and lowland, drought susceptible), has benefited from the existence of larger genetic variability than in other cereals. This can be successfully exploited using marker-assisted breeding.

Drought Tolerance in Maize: Indirect Selection through Secondary Traits versus Genomewide Selection

ABSTRACTPhenotyping maize (Zea mays L.) for drought tolerance is costly and time consuming. Our objectives were to determine (i) the heritability, genetic variance, and genetic correlations for grain yield and secondary traits in maize under drought and (ii) the efficiency of indirect selection through secondary traits versus genomewide selection. Testcrosses of 238 recombinant inbreds from the intermated B73 × Mo17 population were evaluated in multilocation trials under managed drought and nondrought (control) conditions in Minnesota in 2009 and 2010. Mean grain yield under drought was 52% of the mean grain yield in the control experiments. Heritability for grain yield was 0.37 ± 0.08 under drought and 0.60 ± 0.04 in the control experiments. Indirect selection based on anthesis‐silking interval, leaf senescence, leaf chlorophyll content, or grain yield in control conditions was not predicted to be more efficient than direct selection for grain yield under drought. Genomewide selection (with 998 markers) for grain yield under drought had a predicted relative efficiency of 1.24. Genetic correlations estimated from genomewide marker effects agreed well with correlations estimated from genetic covariances. Given that multiple cycles of marker‐based selection can be done per year in maize and that genotyping is cheaper than phenotyping for drought tolerance, our results suggest that genomewide selection could increase genetic gains per unit time for grain yield under drought.

Selection Strategy for Sorghum Targeting Phosphorus‐limited Environments in West Africa: Analysis of Multi‐environment Experiments

ABSTRACTAlthough sorghum [Sorghum bicolor (L.) Moench] in West Africa (WA) is generally cultivated with limited or no fertilization on soils of low phosphorus availability, no assessments of the genetic variation among WA sorghum varieties for adaptation to low soil P are known. We assessed grain yields of 70 diverse sorghum genotypes under −P (no P fertilization) and +P conditions at two locations in Mali over 5 yr. Genetic variation for grain yield under −P conditions and the feasibility and necessity of sorghum varietal testing for grain yield under −P conditions were evaluated. Delayed heading dates (0–9.8 d) and reductions of grain yield (2–59%) and plant height (13–107 cm) were observed in −P relative to the +P trials. High estimates of genetic variance and broad‐sense heritabilities were found for grain yield across both −P (h2 = 0.93) and +P (h2 = 0.92) environments. The genetic correlation for grain yield performance between −P and +P conditions was high (rG = 0.89), suggesting that WA sorghum varieties generally possess good adaptation to low‐P conditions. However, genotype × phosphorus crossover interaction was observed between some of the highest yielding genotypes from the −P and +P selected sets, with the variety IS 15401 showing specific adaptation to −P. Direct selection for grain yield in −P conditions was predicted to be 12% more efficient than indirect selection in +P conditions. Thus, selection under −P conditions should be useful for sorghum improvement in WA.

Implications of direct and indirect selection parameters for improvement of grain yield and quality components in Chenopodium quinoa Willd.

The present study was undertaken to evaluate direct and indirect selection criteria for the improvement of grain yield and quality components in Chenopodium quinoa Willd. Correlated response (CR) and relative selection efficiency (RSE) were estimated for grain yield and three quality components, grain protein, grain carotenoid and leaf carotenoid based on different contributing traits. Stem diameter, chlorophyll a, total chlorophyll and leaf carotenoid had high CR and RSE values for grain yield indicating the effectiveness of these traits in increasing grain yield. Grain protein and grain carotenoid exhibited negative CR and RSE values for grain yield indicating that direct selection for grain yield would lead to a slight decrease in these quality characters. Grain size was not of much significance either in increasing grain yield or any of the quality components. Grain yield can also be increased through indirect selection for stem diameter, while leaf pigments are likely to play a major role in enhancement of quality traits like leaf and grain carotenoid.

Full-sib reciprocal recurrent selection in the maize populations Cimmyt and Piranão

We estimated the genetic gains of the 12th cycle of reciprocal recurrent selection for maize traits of agronomic interest. We used 23 ISSR molecular markers in an attempt to maximize genetic variability among and within populations based on selection of S(1) progenies. To this end, 138 full-sib families were evaluated in a randomized block design in two environments (the municipalities of Campos dos Goytacazes and Itaocara, in the State of Rio de Janeiro, Brazil), with replications within sets. Direct selection for grain yield was used for the selection of the families. To assess genetic diversity among and within populations, we examined plants produced from part of the S(1s) seeds from the parents that originated the 42 full-sib families that were selected from the agronomic traits. Direct selection for grain yield provided good gains for the traits evaluated, with estimated improvement of -0.87 days for days to flowering, 0.35 plants, 1.79 ears per plot, 0.58 g per 100-grain weight, 308.21 g ear weight per plot, and 261.83 kg/ha grain yield. Application of molecular markers at the stage of superior progeny selection led to increased genetic distance among populations, which is a very important factor for utilization of heterosis and providing greater longevity to the reciprocal recurrent selection program.