Root Lodging Research Articles

Genomewide Prediction Accuracy within 969 Maize Biparental Populations

ABSTRACTIn genomewide selection, the expected correlation between predicted and true genotypic values (rMG) has been previously derived as a function of the training population size (N), heritability (h2), and effective number of chromosome segments (Me) affecting the trait. Our objectives were to determine: (i) the mean and variability of rMG in 969 biparental maize (Zea mays L.) breeding populations for seven traits, (ii) if rMG can be predicted in advance, and (iii) how N, h2, and number of markers (NM) affect rMG. We modified a previous equation for expected rMG to account for linkage disequilibrium (r2) between a marker and a quantitative trait locus (QTL). Across the 969 populations, the mean and range (in parentheses) of observed rMG was 0.45 (−0.59, 1.03) for grain yield, 0.59 (−0.34, 0.96) for moisture, 0.55 (−0.24, 1.10) for test weight, 0.49 (−0.22, 1.04) for stalk lodging, 0.41 (−0.30, 0.93) for root lodging, 0.47 (−0.45, 0.97) for plant height, and 0.42 (−0.43, 0.94) for ear height. The observed rMG values were centered around the expected rMG when r2 was accounted for, but the observed rMG had a large spread around the expected rMG. The r2(Nh2)1/2 had the strongest association with observed rMG. When r2(Nh2)1/2 exceeded 8, the proportion of rMG equal to or larger than 0.50 reached 90% among all the population–trait combinations. We conclude it is difficult to predict rMG in advance, but that rules of thumb based on r2(Nh2)1/2 can help achieve a high rMG.

Root lodging tolerance in Helianthus annuus (L.): associations with morphological and mechanical attributes of roots

Background and aims The objectives of this study were to quantify the morphological and mechanical properties of the root-plate within two sunflower hybrids of contrasting susceptibility to root lodging; and to evaluate the effects of crop population density on these properties at two different development stages.

Inheritance of the stay-green trait in tropical maize

Stay-green maize genotypes have been associated with tolerance to biotic and abiotic stresses, including tolerance to drought, and to stalk and root lodging, but there is limited information on its inheritance. Thus, this research was conducted to study the inheritance of the stay-green trait using both conventional analysis and QTL mapping of the Design III in a tropical maize population developed from two inbred lines genetically divergent for this trait. Two-hundred and fifty F2 plants were genotyped with 177 microsatellite markers, and their backcrossed progenies to both parental inbreds were evaluated at three locations. Ten plants per plot were assessed 120 days after sowing and the plot means scores for stay-green, adjusted for days to silking emergence, were used for analysis. The additive variance was larger than the dominance variance, the genetic by location interaction variance presented a high magnitude, and the heritability coefficient on a plant-basis a low magnitude. Seventeen QTL were mapped, most of them were clustered on four chromosomes and accounted for by 73.08 % of the genetic variance. About half of the QTL interacted with location, and the average level of dominance was partial dominance. The additive effects were larger than the dominance effects; the latter were not unidirectional, so that heterosis could not be exploited in crosses. Procedures for marker-assisted selection to increase the level of stay-green are discussed and an approach is suggested for using both stable and non-stable QTL in a marker-assisted backcross program.

Phenotypic characterization of a mini cor collection for increased grain quality in maize

Agronomic traits of 18 populations comprising a mini core collection for increased grain quality of the Maize Research Institute Zemun Polje were studied, along with two standard kernel type commercial hybrids. For almost all the traits (except root lodging) a considerable genetic variability was found, enabling successful breeding for any of them using this populations. Based on the obtained results, two populations were found to have grain yield at the level of ZP 341 commercial hybrid (one of them is from former Yugoslavia, and another is the introduced one). These two populations will be first to introduce into commercial breeding programs, if it proves they have also favorable biochemical characteristics. On the other hand, three populations had grain yield in the range of 1, 60-1, 91 t/ha, that is even lower than for commercial inbreeds. They will be excluded from the further breeding programs. Most of the populations were earlier than the commercial hybrids, during vegetation and according to the grain moisture at harvest. This is very favorable from a breeding standpoint. The worst characteristic of the population was very high stalk lodging, compared to commercial checks.

Combining Ability and Acceptability of Temperate Sweet Corn Inbreds Derived from Exotic Germplasm

Excellent table quality is an essential characteristic of commercial sweet corn (Zea mays) and commonly held paramount as a selection criterion. As a consequence, breeding for improved agronomic performance in sweet corn has been limited in comparison with United States dent corn breeding efforts. The narrowness of genetic diversity within modern sweet corn germplasm suggests potential exists for yield enhancement through new heterotic combinations and introgression of sources of improved agronomic performance. The objective of this study was to examine the results of incorporating nonsweet germplasm in the development of improved temperate sweet corn cultivars. Five inbreds derived from crosses between nonsweet germplasm and temperate supersweet (shrunken2, sh2) inbreds were crossed with three temperate sh2 testers to make 15 experimental hybrids. The hybrids were evaluated in four environments with three replications per environments. Experimental entry Wh04038V × Tester2 yielded 18.1 Mg·ha−1 in 2009 and 16.6 Mg·ha−1 in 2010, significantly out-yielding the top producing commercial control, ‘Overland’, in both years. An additional six entries derived from exotic-by-temperate crosses yielded significantly more than all commercial checks in 2009. Four specific experimental entries consistently exhibited superior resistance to root lodging, northern corn leaf blight (Exserohilum turcicum), and Maize dwarf mosaic virus (MDMV) compared with ‘Marvel’ and ‘Supersweet Jubilee Plus’. Ten of the 15 experimental entries exhibited similar quality for flavor relative to ‘Marvel’ and ‘Overland’, however ‘Supersweet Jubilee Plus’ outperformed all entries for both flavor and tenderness, suggesting that while incorporation of nonsweet germplasm in sweet corn breeding programs may provide valuable contributions for yield and agronomic performance, flavor and tenderness must be carefully regarded.

English

  Trials were carried out using five composite maize varieties in a Striga lutea (Lour) endemic soil of Temidire-Eruwa, Oyo State, Nigeria, in 2004 and 2005. The composite maize varieties were tested under varied fertilizer types, nitrogen (N) concentrations and artificial striga infestation. The objective was to test these striga resistant maize varieties for yield and agronomic performance under the above conditions. The result showed that, variety and year of evaluation differed significantly (P<0.01) for almost all agronomic characters such as plant stand, days to anthesis (silking and tasselling), plant and ear heights as well as root and stalk lodging resistance at both 100 and 200 kgN/ha. Variety x year interaction were also significantly different (P<0.01) for all agronomic characters except root lodging and husk tip cover. Fertilizer type differed only for days to silking, plant height and plant aspect, while year x nitrogen source and variety x nitrogen source was highly significant (P<0.01) for field weight. Plant stands were generally better in 2004 than 2005 for all varieties except Acr 97syn-W and DMR-LSR-W. The composite maize varieties were able to tolerate high N-concentration except DMR-LSR-Y which do not utilize excess nitrogen above 100 kgN/ha. Use of striga resistant maize varieties concomitantly with nitrogen fertilizer is recommended for farmers in S. lutea endemic ecology, for higher grain yield.   Key words: Composite maize, fertilizer type, nitrogen (N) concentrations, striga resistance, yield.

Evaluación de híbridos experimentales de maíz del PRM en Cenroamérica.

Evaluation of experimental corn hybrids from PRM in Central america. The trial of experimental white corn hybrids from PRM-2001 was evaluated in 14 localities in Central America during 2001. The objective was to assess their grain yield and agronomic characteristics of the experimental hybrids. Twelve triple hybrids and one double hybrid, bred from simple crosses from CIMMYT and superior lines from different PRM projects, mainly of hybrids and stunting , including one reference entry (CML 247 x CML 254) and on control, were evaluated. A Complete Randomized Experimental Block design with three replication was used. The variables registered were: grain yield, ear rot, male and female flowering, ear covering and aspect, root and stalk lodging. The results obtained for grain yield, through the 14 environments, varied between 4.75 to 6.37 t/ha, with a general media of 5.60 t/ha and variation coefficient of 9.9%. In ear rot, the hybrids showed values of 4.3 and 8.0%, being lower than the controls.

Observational Study on the Recovery from Root Lodging at Flowering Time and Yield Reduction in Maize (Zea mays L.)

On August 2, 1999, the typhoon Olga with the maximum wind speed of 19.2 m/s hit the Korean peninsula and caused considerable damage to crops. Regional yield trials were at tasseling stage and were affected by the typhoon. After the storm, almost all the plants were root-lodged. This provided a rare chance to study the relationship between recovery from the lodging and reduction of grain yield in maize. Three check cultivars were examined for angle of lodging, grain yield, yield components, plant height and ear height. Six levels of leaning were classified. Plants leaning less than 10 o from the vertical were considered as non-lodged. Average reduction in grain yield across five levels of lodging was 29.2% with the mean of 46.1 o . The reductions of three hybrids were 25% for Suwon 19, 39.5% for Pioneer 3525 and 27.4% for DeKalb 689. R 2 values of grain yield on angles of lodging ranged from 0.33 for Suwon 19 to 0.51 for Pioneer 3525. The slope of the regression was lowest for Suwon 19 and highest for Pioneer 3525. Yield reduction from lodging was less severe for the locally bred Suwon 19. Reductions in yield components were also influenced by cultivars with Pioneer 3525 showing the most severe reduction. The yield components most severely affected by root lodging at the flowering time were ear length and number of kernels per row. The high reductions in yield and agronomic traits caused by root lodging justify the lodging resistance as a major breeding objective in Korea.

Biomechanics of nodal, seminal and lateral roots of barley: effects of diameter, waterlogging and mechanical impedance

Biomechanical properties of cereal root systems largely control both resistance to root lodging and their ability to stabilise soil. Abiotic stresses can greatly modify root system growth and form. In this paper the effect of waterlogging and moderate mechanical impedance on root biomechanics is studied for both lateral roots and the main axes of barley. Barley (Hordeum vulgare) plants were subjected to transient water-logging and moderate mechanical impedance in repacked soil columns. Roots were excavated, separated into types (nodal, seminal or lateral) and tested in tension to measure strength and elastic modulus. Water-logging and mechanical impedance substantially changed root system growth whilst root biomechanical properties were affected by waterlogging. Root strength was generally greater in thin roots and depended on root type. For example, seminal roots 0.4–0.6 mm in diameter were approximately seven times stronger and five times stiffer than lateral roots of the same diameter when mechanically impeded. Root sample populations typically exhibited negative power-law relationships between root strength and diameter for all root types. Mechanical impedance slowed seminal root elongation by approximately 50 % and resulted in a 15 % and 11 % increase in the diameter of in nodal and seminal roots respectively. Power-law relationships between root diameter and root biomechanical properties corresponded to the different root types. Coefficients for between root diameter, strength and elastic modulus improved when separated by root type, with R2 values increasing in some roots from 0.05 to 0.71 for root strength and 0.08 to 0.74 for elastic modulus. Moderate mechanical impedance did not influence the tensile strength of roots, but, waterlogging diminished the relationship between root strength and diameter. Separation of root type improved predictions of root strength and elastic modulus using power-law regressions.

Effects of elevated [CO2] on stem and root lodging among rice cultivars

Studies showed that elevated [CO2] would improve photosynthetic rates and enhance yields of rice; however, few studies have focused on the response of rice lodging, which is a major cause of cereal yield loss and quality reduction, under elevated [CO2]. In this study, we examined the effects of elevated [CO2] on stem and root lodging using 4 rice cultivars (86Y8, japonica hybrid; LYP9, 2-line indica hybrid; variety 9311, type of indica inbred rice, and SY63, 3-line indica hybrid) grown under two [CO2] levels: 400 and 680 μmol mol−1. Our results indicated that under elevated [CO2], the stem-lodging risk (SLR) of 9311 decreased, while in SY63 the SLR increased, 86Y8 and LYP9 were not significantly affected; the risk of root lodging was reduced for all cultivars, because root biomass (instead of root number) and bending strength were increased significantly, and then the increase of anti-lodging ability is far higher than that of self-weight mass moment for all cultivars. These findings suggested that higher [CO2] can enhance the risk of stem-lodging for cultivars with strong-[CO2]-responses, but may not aggravate the root lodging for all rice cultivars.

Genetic distance among doubled haploid maize lines and their testcross performance under drought stress and non-stress conditions

In contrast to conventional inbreeding that takes up to seven generations to develop inbred lines, the doubled haploid (DH) technology allows production of inbred lines in two generations. The objectives of the present study were to: (a) evaluate testcross performance of 45 doubled haploid lines under drought stress and non-stress conditions (b) estimate heritabilities for grain yield and other traits and (c) to assess the genetic distance and relationship among the DH lines using 163,080 SNPs generated using genotyping-by-sequencing (GBS). The 45 hybrid and five checks were evaluated using a 10 × 5 alpha lattice in six drought stress and nine well-watered environments in Kenya, Uganda, and Tanzania. Differences in trait means between the drought stress and well-watered conditions were significant for all measured traits except for anthesis date. Genetic variances for grain yield, grain moisture, plant height and ear height were high under well-watered environments while genetic variance for anthesis date, root lodging and stalk lodging were high under drought stress environments. Combined analyses across drought stress and well-watered environments showed that ten top hybrids produced 1.6–2.2 t/ha grain yield under well-watered condition and 1–1.4 t/ha under drought stress condition higher than the mean of the commercial checks. Genetic distance between pairwise comparisons of the 38 of the 45 DH lines ranged from 0.07 to 0.48, and the overall average distance was 0.36. Both cluster and principal coordinate analysis using the genetic distance matrix calculated from 163,080 SNPs showed two major groups and the patterns of group was in agreement with their pedigree. Thirteen (13) of the best hybrids are currently in National Performance Trials testing, an important step towards commercialization in Kenya, Tanzania and Uganda.

Root‐lodging resistance in maize as an example for high‐throughput genetic mapping via single nucleotide polymorphism‐based selective genotyping

AbstractLarge‐scale selective genotyping and high‐throughput analysis are two important strategies for low‐cost and high‐effective genetic mapping. In this study, selective genotyping was applied to four maize F2 populations. Thirty plants were selected from each of the two tails of the original F2 populations to represent extreme resistant and susceptible plants to root lodging, and genotyped individually with 1536 single nucleotide polymorphisms (SNPs). A quantitative trait locus (QTL) was declared when at least three closely linked SNPs showed significant allele frequency difference between the two tails. Nine QTL were identified for root lodging across the four populations, which were located on chromosomes 2, 4, 5, 7, 8 and 10 and one of them was shared between two populations. A total of 20 segregation distortion regions (SDRs) were identified across the four populations, one of which was co‐localized with a QTL on chromosome 4. The tightly linked SNPs identified in this study can be used for marker‐assisted selection for root lodging. Selective genotyping, when combined with pooled DNA analysis, can be used to develop strategies for high‐throughput genetic mapping for all crops.

Effect of Planting Density on Root Lodging Resistance and Its Relationship to Nodal Root Growth Characteristics in Maize (Zea mays L.)

Increase of planting density has been widely used to increase grain yield in maize. However, it may lead to higher risk of root lodging hence causing significant yield loss of the crop. The objective of this study was to investigate the effect of planting density on maize nodal root growth characteristics and to analyse their relationships to root lodging resistance. Field experiment was conducted in 2010 and 2011, using two maize varieties, Zhengdan 958 (ZD) and Xianyu 335 (XY), under three planting densities, viz., 4.50, 8.25 and 12.00 plants m-2. The results showed the root failure moment, an indicator of root lodging resistance, was significantly affected by the planting density, the maize variety, as well as the crop developmental stages, and was decreased with increasing planting density. The number and the average diameter of the roots on the upper internodes (phytomer 5 to 8) were decreased with increasing planting density, whereas the maize variety had little effects on those variables. On the contrary, the root angle was less responsive to planting density but was significantly affected by the variety being that XY had larger root angle than did ZD. The root failure moment was linearly positively correlated with the total root number and the average root diameter on the upper internodes, indicating that a greater root number and a larger root diameter are important traits for enhancing root lodging resistance in maize plants.

Genomewide predictions from maize single-cross data

Maize (Zea mays L.) breeders evaluate many single-cross hybrids each year in multiple environments. Our objective was to determine the usefulness of genomewide predictions, based on marker effects from maize single-cross data, for identifying the best untested single crosses and the best inbreds within a biparental cross. We considered 479 experimental maize single crosses between 59 Iowa Stiff Stalk Synthetic (BSSS) inbreds and 44 non-BSSS inbreds. The single crosses were evaluated in multilocation experiments from 2001 to 2009 and the BSSS and non-BSSS inbreds had genotypic data for 669 single nucleotide polymorphism (SNP) markers. Single-cross performance was predicted by a previous best linear unbiased prediction (BLUP) approach that utilized marker-based relatedness and information on relatives, and from genomewide marker effects calculated by ridge-regression BLUP (RR-BLUP). With BLUP, the mean prediction accuracy (r(MG)) of single-cross performance was 0.87 for grain yield, 0.90 for grain moisture, 0.69 for stalk lodging, and 0.84 for root lodging. The BLUP and RR-BLUP models did not lead to r(MG) values that differed significantly. We then used the RR-BLUP model, developed from single-cross data, to predict the performance of testcrosses within 14 biparental populations. The r(MG) values within each testcross population were generally low and were often negative. These results were obtained despite the above-average level of linkage disequilibrium, i.e., r(2) between adjacent markers of 0.35 in the BSSS inbreds and 0.26 in the non-BSSS inbreds. Overall, our results suggested that genomewide marker effects estimated from maize single crosses are not advantageous (cofmpared with BLUP) for predicting single-cross performance and have erratic usefulness for predicting testcross performance within a biparental cross.

Trends of grain yield and plant traits in Chinese maize cultivars from the 1950s to the 2000s

Retrospective analyses may provide an understanding of unexploited genetic potential and indicate possible pathways for future yield improvement. The objectives of this study were to present maize(Zea mays L.)yield trends and plant traits changes for maize cultivars from the 1950s to the 2000s in China. Trials were conducted at three locations in 2007 and 2008, and at four locations in 2009. Twenty-seven single hybrids, four double-cross hybrids, and four open-pollinated varieties, were grown at three densities at each location each year. 56% of total yield gain was contributed to breeding from 1950 to 2000. New hybrids had more resistance to compound stress. Levels of response of all hybrids to higher-yielding environments were similar, and greater than that of OPVs. All maize cultivars showed morphological changes for all characteristics tested in a volatile manner from 1950 to 2000, except for relatively stable leaf number. ASI decreased and tolerance to root lodging improved, which were enhanced at higher plant densities. There were no trends for other characteristics at higher densities. Shorter maturity, smaller plant size and more tolerance to root and stalk lodging will be required for further yield improvement. Chinese maize yield improvement can benefit from agronomic strategies at higher plant densities.

QTL mapping and epistasis analysis of brace root traits in maize

Root architecture is a major factor influencing root lodging, which limits greater yield stability at high planting density. Total brace root tier number (TBRTN) and effective brace root tier number (EBRTN) are the two most important root architecture traits influencing root lodging. However, the genetic mechanisms that underlie these traits remain poorly understood. In this study, quantitative trait loci (QTL) for TBRTN and EBRTN were mapped using a set of 201 recombinant inbred lines (RILs) and 278 immortalized F2 (IF2) populations derived from these RILs, which were evaluated in three environments. Ten QTL in the RILs and 15 QTL in the IF2 population were detected. In the two populations, we identified two coincident major QTL for TBRTN and a single identical major QTL for EBRTN. The QTL for TBRTN showed the largest additive effect, accounting for 16.36 and 17.88% of the phenotypic variance in the RILs and IF2 population, respectively. Additional epistatic effects were identified for all the maize chromosomes, except for chromosome 4. Most epistatic effects involved pairs of loci that were on different chromosomes. At the same time, we found loci that interacted simultaneously with several other loci to affect expression of the traits, which was particularly evident in the IF2 population. For example, qTAR1-2 interacted simultaneously with qTAR2-1, qTAR3-1, qTAR5-1, and qITAR8-2 to affect the expression of TBRTN. Therefore, a complex network controlling the traits was found in maize. These results provide useful information for understanding the molecular mechanisms controlling root architecture.

Selection and Adaptation to High Plant Density in the Iowa Stiff Stalk Synthetic Maize (Zea mays L.) Population

The plant density at which maize (Zea mays L.) hybrids achieve maximum grain yield has increased throughout the hybrid era, whereas grain yield on a per plant basis has increased little. Changes in grain yield, grain moisture, test weight, and stalk and root lodging have been well characterized in comparisons of commercial hybrids representing different eras of hybrid maize production but have yet to be examined in a recurrent selection program. The objective of this experiment was to determine if direct selection for grain yield and agronomic performance in the Iowa Stiff Stalk Synthetic (BSSS) population has indirectly improved adaptation to high plant density. Material from an unselected base population, BSSS, was compared to the most advanced cycles of selection from three different recurrent selection programs at seven Iowa locations in 2008 and 2009. Populations were compared at densities of 38,300, 57,400, 77,500, and 95,700 plants ha−1. Treatments were replicated twice at each location and arranged in a split plot design. Selection produced notable improvement in adaptation to high plant density for grain yield and stalk lodging. Selection did not have large impacts on density response for root lodging, test weight, or grain moisture. Because of the improvement in density response for grain yield and stalk lodging without major negative changes in other traits, our data suggest that selection has improved adaptation to high plant density in these populations.

Raising yield potential of wheat. III. Optimizing partitioning to grain while maintaining lodging resistance

A substantial increase in grain yield potential is required, along with better use of water and fertilizer, to ensure food security and environmental protection in future decades. For improvements in photosynthetic capacity to result in additional wheat yield, extra assimilates must be partitioned to developing spikes and grains and/or potential grain weight increased to accommodate the extra assimilates. At the same time, improvement in dry matter partitioning to spikes should ensure that it does not increase stem or root lodging. It is therefore crucial that improvements in structural and reproductive aspects of growth accompany increases in photosynthesis to enhance the net agronomic benefits of genetic modifications. In this article, six complementary approaches are proposed, namely: (i) optimizing developmental pattern to maximize spike fertility and grain number, (ii) optimizing spike growth to maximize grain number and dry matter harvest index, (iii) improving spike fertility through desensitizing floret abortion to environmental cues, (iv) improving potential grain size and grain filling, and (v) improving lodging resistance. Since many of the traits tackled in these approaches interact strongly, an integrative modelling approach is also proposed, to (vi) identify any trade-offs between key traits, hence to define target ideotypes in quantitative terms. The potential for genetic dissection of key traits via quantitative trait loci analysis is discussed for the efficient deployment of existing variation in breeding programmes. These proposals should maximize returns in food production from investments in increased crop biomass by increasing spike fertility, grain number per unit area and harvest index whilst optimizing the trade-offs with potential grain weight and lodging resistance.

Testcross Response to Four Cycles of Half‐sib and S2 Recurrent Selection in the BS13 Maize (Zea mays L.) Population

ABSTRACTInbred progeny recurrent selection has been shown to be theoretically superior to several forms of noninbred‐progeny recurrent selection. However, recent improvements to theory and empirical evidence suggest that inbred‐progeny recurrent selection is not a superior method of recurrent selection. In the BS13(S) population, inbred‐progeny recurrent selection has not been effective at improving population per se performance. However, no other selection programs have been evaluated in BS13(S), so there is no basis to compare inbred‐progeny recurrent selection in BS13(S) to other methods to determine if other methods might be more effective. Four cycles of half‐sib selection with inbred line B97 as tester have been completed. The first four cycles of half‐sib selection and first four cycles of inbred‐progeny selection were testcrossed to B97 and evaluated in a replicated experiment in 2007 and 2008. Half‐sib selection improved grain yield, grain moisture, stalk lodging, root lodging, test weight, and final plant density, whereas inbred‐progeny selection did not improve any of these traits. This study adds to growing empirical literature suggesting that inbred‐progeny recurrent selection is inferior to noninbred‐progeny selection methods. A hypothesis has been put forth that pseudo‐overdominance caused by linkage disequilibrium may have limited response to inbred‐progeny recurrent selection in BS13(S) as well as other maize populations.

Combining ability of early-maturing quality protein maize inbred lines adapted to Eastern Africa

Adapted early-maturing quality protein maize (QPM) hybrids with high grain yield potential in Eastern Africa would benefit maize farmers through increased grain production and subsequently higher income but they are not widely available. Fourteen early-maturing QPM inbred lines developed from POOL15QPM-SR, were crossed using the diallel mating design. The resulting single-cross hybrids were evaluated under six well-watered, drought stress and low nitrogen conditions at six locations in Eastern Africa. The objectives were to assess the grain yield potential of early-maturing F 1 QPM hybrids, estimate the general combining ability (GCA) and specific combining ability (SCA) for grain yield and other agronomic traits and determine the relationship between grain yield and other agronomic traits of the QPM hybrids. Days to anthesis, days to silking, anthesis–silking interval, ears per plant, root and stalk lodging, ear aspect, and grain yield were measured. Variation among hybrids was significant for all traits except root lodging. The best single-cross hybrid across environments was POOL15QPMFS538-B-3-B-B × POOL15QPMFS462-B-4-B-B (5.30 t ha −1). Mean squares due to GCA were significant, whereas mean squares due to SCA were not for measured traits indicating that additive genetic effects were much more important in this set of genotypes. Inbred line POOL15QPMFS538-B-3-B-B exhibited very good GCA effects for grain yield in well-watered environments and across environments for grain yield (0.74 t ha −1). Inbred line Pool15QPMFS478-B-3-B-B had the best GCA effect for grain yield under managed drought stress (0.26 t ha −1), while inbred line POOL15QPMFS319-B-2-B-B had the best GCA effect (−1.11 days) for reduced days to anthesis across environments. The new QPM inbred lines with desirable traits could be used to improve grain yield and protein quality of maize breeding programs in Eastern Africa.