Cross Maize Hybrids Research Articles

Performance of Single Cross Maize Hybrids for Summer Planting in Western Nepal

In addition to being a major source of food, feed, and fodder, maize is one of the important cereals for the livelihood of hill farmers in Nepal. Low maize productivity in the western hills of Nepal has traditionally been associated with the absence of high yielding varieties. The purpose of this study was to find single cross maize hybrids that would be highly productive and adaptable for summer planting in western hills of Nepal. An alpha lattice design with three replications was used to evaluate one hundred single cross hybrids, including checks at NMRP, Rampur; DoAR, Surkhet; and DoAR, Doti during the summer season of 2019. In the evaluated maize hybrids, all measured traits showed significant genetic variation, indicating the presence of substantial genetic diversity among tested hybrids and significant genotype by environmental interaction highlighting the variable performance across locations. RML-145/RL-105, RML-97-1/RML-98, RML-145/RML-146, RML-138/RML-2, and RML-97-2/RL-105 was among the top 17 hybrids with grain yields of 8-9 t ha1. Significant correlations of grain yield with plant height, ear height, test weight, cob length, and cob diameter suggest that these are the important traits while selecting the hybrids for yield. The study also employed 20 SSR markers to explore genetic diversity of 25 inbred lines which were used for developing top yielding hybrids, grouped these inbred lines into five distinct cluster showed moderate genetic diversity, and higher yield performance of hybrids associated with diverse background of parental lines. The genotype by environment interactions highlights the importance of multilocation testing to ensure consistent or location specific performance across varied conditions. The results suggest the possibility of exploring high yielding, adaptive, and location specific hybrids that can help to enhance maize productivity of western Nepal and narrow down the yield gap.

Elucidating the genetic potential of hybrids derived from elite maize (Zea mays L.) inbreds for economic traits under North-Western Himalayan condition

Abstract This study was conducted to evaluate the combining ability of newly acquired maize inbred lines over the environments. Twenty-eight crosses developed by crossing eight elite inbreds in a half-diallel mating design were evaluated during kharif, 2019 for 12 agro-morphological traits in RBD with two replications at two different environments reflecting diverse agro-climatic and ecological conditions of North-Western Himalayas (SAREC, Kangra and HAREC, Bajaura). Analysis of variance showed that there was sufficient amount of genetic variability in the material studied. In accordance to Bartlett’s test, error variance was homogeneous only for six traits. Estimates of σ2SCA were higher as compared to σ2GCA both within and across environments for all the traits, except days to 75 per cent brown husk at Kangra, representing prevalence of non-additive gene action for these traits. The inbred line B73 at Bajaura, and LM14 at Kangra were found to be good general combiner for most traits. The inbreds with good GCA can be used as potential parents for the development of high yielding single cross maize hybrids. The hybrid combinations namely, B73 × BAJIM1811 and BAJIM1522 × BAJIM1811 were identified as potentially superior ones at Kangra and Bajaura environments. The identified promising hybrids need further assessment for their superiority in performance across the locations and over years. Keywords: General combining ability, specific combining ability, gene action and maize.

Evaluation of the Performance of Single Cross Maize Hybrids and Their Parents in the Spring and Autumn Seasons

Evaluation of the Performance of Single Cross Maize Hybrids and Their Parents in the Spring and Autumn Seasons

Genomic prediction in multi-environment trials in maize using statistical and machine learning methods

In the context of multi-environment trials (MET), genomic prediction is proposed as a tool that allows the prediction of the phenotype of single cross hybrids that were not tested in field trials. This approach saves time and costs compared to traditional breeding methods. Thus, this study aimed to evaluate the genomic prediction of single cross maize hybrids not tested in MET, grain yield and female flowering time. We also aimed to propose an application of machine learning methodologies in MET in the prediction of hybrids and compare their performance with Genomic best linear unbiased prediction (GBLUP) with non-additive effects. Our results highlight that both methodologies are efficient and can be used in maize breeding programs to accurately predict the performance of hybrids in specific environments. The best methodology is case-dependent, specifically, to explore the potential of GBLUP, it is important to perform accurate modeling of the variance components to optimize the prediction of new hybrids. On the other hand, machine learning methodologies can capture non-additive effects without making any assumptions at the outset of the model. Overall, predicting the performance of new hybrids that were not evaluated in any field trials was more challenging than predicting hybrids in sparse test designs.

Estimates of Combining Ability and Association among Morpho-Agronomic Traits of Single Cross Maize (Zea mays L.) Hybrids

Screening genotypes have a crucial role to increase the efficiency of selections in plant breeding program. Therefore, this study was emphasized to determine combining ability and the association between traits among themselves and yield. The experiment was conducted at Haramaya University Research Station (Raare) for two years (2018 and 2019) using 4x7 alpha-lattice design with three replications. Pooled analysis of variance revealed highly significant (p≤0.01) variations among crosses for grain yield and related traits. According to the result of combining ability analysis, parental line L3 was identified as a good general combiner for grain yield, ear diameter, 1000-kernel weight, and days to maturity. Similarly; L1, L2, and L8 proved as the best general combiner for number of kernels per row. Crosses L1×L6, L3×L5, L4×L6, L4×L8, and L5×L7 were found good specific combiners for 1000-kernel weight. Furthermore, the cross L5×L6 was the best specific combiner for ear diameter, whereas L4×L7 for both number of kernels per row and 1000-kernel weight. Likewise, the crosses L1×L5, L3×L8, L6×L7, and L7×L8 were identified as the best specific combiner towards earliness. Moreover, thousand kernel weight showed significant positive correlation with grain yield, conversely, days to anthesis, days to silking, ear aspect, and Puccinia sorghi exhibited significant negative correlation with grain yield at genotypic and phenotypic levels. Ear length, 1000-kernel weight, number of kernel rows per ear, and Turcicum leaf blight had positive direct effect on grain yield at genotypic and phenotypic level. In general, the result presented in the study might be useful for further breeding process to improve the productivity of maize.

Evaluation of single cross maize hybrids during the spring season in Khairahani, Chitwan, Nepal

The experiment was conducted at Khairahani-5, Chitwan, Nepal from 28th February to 20th June 2021. Twenty single cross maize hybrids were evaluated for quantitative and qualitative traits. The experiment was conducted in a randomized complete block design (RCBD) with three replications. Data were recorded on flowering traits, physiological and disease traits, agro-morphological traits, and yield and yield contributing traits. Analysis of variance showed significant differences in all traits except for root lodging, the number of plants per hectare, leaf senescence, and plant aspect. The result indicated that HGABS2-15-2-1B/RL174 had the shortest days to anthesis and silking. The genotype RML138/RML140 was found to have double cob. The longest cob was found in RML76/RML146 (17.3 cm), while the highest cob diameter was found in the Shrestha (5.1cm). The maximum number of grains per row was obtained from RML57/RL174, while the highest thousand-grain weight was obtained in RAMPUR HYBRID-10. Shrestha variety produced highest grain yield (9.954tha-1) followed by RML191/RML18 (9.41tha-1), CAH1715 (9.356tha-1) and RML4/RL111 (9.021tha-1). The traits with the highest broad-sense heritability were the number of rows per ear (79%), days to fifty percent silking (75%), days to fifty percent anthesis (72%), thousand-grain weight (70%), and grain yield (68%). Correlation studies suggested that the number of ears per hectare, cob length, and thousand-grain weight showed a positive and significant correlation with grain yield. Therefore, RML191/RML18, CAH1715, and RML4/RL111 showed better performance in terms of grain yield.

Comparative study of simple interline and three-way cross maize hybrids

Domestic interline maize hybrids are predominantly three-way cross hybrids in structure, and foreign breeding and seed companies prefer simple interline hybrids. In order to improve the competitiveness of domestic breeding, it is necessary to reorient to simple hybrids, which, in turn, requires information on whether simple maize hybrids have an advantage in specific soil and climatic areas. The purpose of the current study was to conduct a comparative study of new simple interline and three-way cross maize hybrids according to grain productivity and uniformity of economically valuable traits under unstable moisture supply. The study was carried out on the experimental field of crop rotation of the laboratory for maize breeding and seed production of the FSBSI “ARC Donskoy” in 2019–2021. The objects of the study were 10 simple and 10 three-way cross new domestic maize hybrids developed by the method of complete topcrosses. The establishment of field trials, records, biometric measurements and phenological observations were conducted in accordance with the methodological recommendations for conducting field trials with maize. There has been found that productivity of simple hybrids (3.49–4.65 t/ha) turned out to be significantly larger than that of three-way cross hybrids (2.84–3.70 t/ha), the mean excess was 0.78 t/ha or 23.6 %. Simple hybrids were characterized with the best uniformity in a length of a vegetation period (V = 0.58–2.13 %), height of maize ear attachment (V = 5.0–11.3 %), plant height (V = 2.8–4.8 %), and, consequently, better harvesting adaptability. There has been found a negative mean correlation (r = –0.49...–0.69) between grain productivity and variation of traits in terms of maturation, plant height and height of maize ear attachment. There has been found no correlation between the structure of interline maize hybrids and such traits as grain harvest moisture, resistance to lodging and smut “virus”. Due to a set of traits there has been identified a new simple interline maize hybrid ‘Zernogradsky 367’.

Agronomic Evaluations of Single Cross Maize (Zea mays L.) Hybrids under Zone 3 of Karnataka

Agronomic Evaluations of Single Cross Maize (Zea mays L.) Hybrids under Zone 3 of Karnataka

Genotype X Environment Interaction Studies in Single Cross Maize Hybrids for Quality Traits under Different Environments

Sixty eight genotypes of maize (48 hybrids, 16 parents and 4 checks were evaluated under three different environments to test their stability. Variance due to genotypes, environments and genotype x environment interactions were found significant for oil content, starch content and protein content. Regression approach by Eberhart and Russel 1966 used to investigate the nature of G x E interaction and for identifying genotypes possessing general and specific adaption. None of the hybrids had stability for all quality traits. For Grain Starch content hybrid EI-1155-1 x EI-2416, for oil content hybrid EI-670-2 x EI-2403 and for Protein content hybrids EI-2187 x EI-2403, EI-536-3 x EI-2403, EI-2176 x EI-561-2,EI-2173 x EI561-7 had higher mean values, non significant deviation from regression and regression coefficient around unity (bi=1) indicating the stable performance in different environment and wider adaptability.

Yield Stability Analysis in Maize Hybrids of Southwest China under Genotype by Environment Interaction Using GGE Biplot

Selecting superior genotypes across different environments is vital for varietal release, crop planting, and commercial use. Therefore, the objectives of this research were to appraise the performance of hybrids approved in recent years in diverse environments, and recommend high-yielding and stable genotypes for wider adaptation. Fourteen single cross maize hybrid genotypes (G), including a check, were implemented across ten environments (E) in two crop seasons (2020 and 2021). The combined analysis of variance revealed that G, E, and their interactive (GEI) significantly (p < 0.01) affected the grain yield. Moreover, the mean grain yield ranged from 9333 kg ha−1 for HH-2 (2021) to 13,195 kg ha−1 for LD-18 (2020). The “which won where” GGE biplot revealed the existence of mega environments with their own best hybrids (LD-18 and LD-29 in 2020; LD-18, LD-19, and YY-1506 in 2021). The “mean vs. stable” GGE biplot suggested that LD-18 and ZY-811, with highest/middle productive and high stability across 10 environments, were closest to the ideal genotype. Furthermore, the “discriminating power vs. representativeness” GGE biplot showed that Xuanwei, Yanshan, Gengma, and Shiling were the most the ideal test environments for hybrid selecting, based on their discriminative ability and representativeness. Therefore, the GGE biplot analysis allowed for an efficient selection of high-yielding and stable maize hybrids to guide ecological planting and commercial use.

Assessing the Fodder Potentials of Drought-Tolerant Maize (Zea mays L.) Hybrids in West Africa

The study evaluated the fodder potential of 42 promising drought-tolerant (DT) three-way cross maize (Zea mays L.) hybrids, 11 commercial hybrid checks, and 1 local variety check under irrigation. Agronomic and laboratory trials were conducted to determine their morphological traits and fodder potential. Hierarchical cluster analysis (HCA) to group cultivars into clusters is based on quantity, quality, and the combination of both variables. Selection of potential food-feed cultivars was based on the quantity traits (grain and biomass yield) and quality traits crude protein (CP), in vitro organic matter digestibility (IVOMD), and metabolizable energy (ME). Variation was found for dry matter yield (DMY) at harvest as commercial hybrid recording the maximum DMY of 14.1 t ha−1 and the highest grain yield of 1.4 t ha−1 (P < 0.01), while local check produced a minimum grain yield of 0.54 t ha−1 (P < 0.01) with grain moisture content range between 8.4 and 11.6%. The maximum mean ash content was 5.8% for DT hybrids. Average CP was the highest in commercial hybrids with a value of 6.1%. The mean values for ME were similar (P > 0.01) in both commercial hybrids (7.2 MJ/kg DM) and DT hybrid (7.2 MJ/kg DM), while the highest ME (7.6 MJ/kg DM) was recorded for the local check. Ranking of the hybrids based on grain yield, DMY, CP, ME, and IVOMD showed that cluster subgroup A3 (M1124–24, M1527-7, 30F32, and M1427-6) and A4 (M1427-3, SC637, and M1627-11) exhibited the best potential traits and can therefore be recommended for commercial cultivation following adoption trials by farmers.

Effect of planting time on yield and related-traits of 24 three-way cross maize (Zea mays L.) hybrids

Effect of planting time on yield and related-traits of 24 three-way cross maize (Zea mays L.) hybrids

Phule Maharshi-A Single Cross Maize Hybrid for Maharashtra

Phule Maharshi (QMH-1025), a single cross maize hybrid from public sector in Maharashtra is developed from the cross between QMI-1403 x QMI-1401 by hybridization technique. It is high yielding, orange yellow, semi-flint type, midlate maturing, resistant to Maydis leaf blight, Fusarium stalk rot, and moderately resistant to Turcicum leaf blight, Banded leaf & sheath blight and Charcoal rot. It is also resistant to Stem borer (Chilo partellus Sw.) in field condition. It is superior for crude protein and fibre, starch, Mn and Ca over the check Rajarshi and suitable for Kharif and Rabi season. In various states and varietal trials, the maize hybrid QMH1025 consistently recorded best performance. During Kharif season, QMH-1025 recorded 7605 Kg ha-1 grain yield, which was 37.27 percent higher than Rajarshi ( 5540 Kg ha-1) and 24.20 percent higher than the national check Bio.9637( 6123 Kg ha-1). In Rabi season, it recorded 8761 Kg ha-1 grain yield which was 19.60 percent and 29.45 percent higher than the checks Rajarshi (7326 Kg ha-1) and Bio.9637 (6768 Kg ha-1), respectively. Overall QMH-1025 recorded 27.20 percent higher yield ( 8183 Kg ha-1) over the check Rajarshi (6433 Kg ha-1) and 26.95 percent over the national check Bio.9637 (6446 Kg ha-1) in Kharif and Rabi season. The maize hybrid is released under the name ‘Phule Maharshi’ for Kharif and Rabi season for Maharashtra State in 2016.

Mega-environment analysis of maize breeding data from Brazil

The development and recommendation of single cross maize hybrids (SH) to be used in extensive land areas (mega-environments), and in different crop seasons requires many experiments under numerous environmental conditions. The question we asked is if the data from these multi-environment experiments are sufficient to identify the best hybrid combinations. The aim of this study was to critically analyze the phenotype data of experiments of yield, established by a large seed producing company, under a high level of imbalance. Data from evaluation of 2770 SH were used from experiments conducted over four years, involving the first and second crop seasons, in 50 locations of different years and regions of Brazil. Different types of analysis were carried out and genetic and non-genetic components were estimated, with emphasis on the different interactions of the SH with the environments. Results showed that the coincidence of common hybrids in these experiments is normally small. The estimates of the correlations between of the hybrids coinciding in the environments two by two is of low magnitude. The hybrid × crop season interaction was always expressive; however, the interactions of hybrids and other environmental variables were also important. Under these conditions, alternatives were discussed for making with the information obtained from the experiments, can be more efficient on the process to obtain new hybrids by companies.

Optimum Row Ratio for Seed Production of Single Cross Maize Hybrid, Karimnagar Makka-1 for Enhanced Yield and Profitability

This study undertaken during rabi season of 2017 and 2018 at Agricultural Research Station, Karimnagar, Telangana to study the effect of planting row ratios of female: male for seed production of Maize hybrid Karimnagar makka-1. The flowering showed that male inbred has taken 60 days after sowing (DAS) to 50% pollen shedding as against 64 days in both 4:1 and 5:1 row ratios and female showed 50% silking at 63 DAS compared to 66 days in both 4:1 and 5:1 row ratios. The 5:1 row ratio recorded significantly more cob length (18.3 cm). Kernel number (29.5), 100-seed weight (39.3g), grain weight per cob (107.6g), seed yield of (2597 Kg/ha) and net returns (Rs. 3,93,632/ha) compared to 4:1 row ratio (17.9 cm, 27.3, 36.6 g, 99 g, 2094 Kg/ha and Rs. 3,05,132 / ha respectively) indicating 19.3 and 22.5% increased yield and net returns over 4:1 row ratio which in turn resulted significantly higher yield over 3:1 row ratio

Heterosis in relation to genetic divergence in short duration maize (Zea mays L.)

Thirteen lines and three testers were used to produce 39 single cross maize hybrids by line Ítester mating design. The genetic divergence among thirteen lines and three tester of maize were estimated by using Mahalanobis D2 statistic for twelve characters. The genotypes were grouped into five clusters. Cluster I comprised 12 parental genotypes (L1, L2, L3, L4, L5; L6, L7, L8, L9, L11; L12, L13), while Cluster II (T3), III (T1), IV (L10) and V (T2) were mono-genotypic, suggesting more variability in genetic makeup of the genotypes included in these clusters. The correlation coefficients and linear regressions were used to know the effects of parental genetic distance in determining heterosis and per se performance of the hybrids. Parental genetic distance exhibited significant negative association and significant linear regression along with very low coefficient of determination with better parent heterosis (BPH) and non-significant with per se performance of the hybrids. The present investigation, therefore, the parental genetic distance has significant role in determining heterosis and hybrid performance in kharif maize.

Genetic insights on single cross maize hybrid and its importance on maize self-sufficiency in Nepal

When the world's population rises, total crop production worldwide is not meeting rising food demand. Focus on developing high yielding single cross hybrids of maize that are resource-efficient under diverse soil and climatic conditions is utmost for countries like Nepal. With the aim of exploring genetic reasons for higher hybrid vigor of single cross hybrid of maize, global genetic importance and addressing the emerging issue of needed higher productivity in Nepal to achieve maize self-sufficiency status, comprehensive review work was performed. Research findings explored that; the Heterosis hypothesis has been widely exploited in crop breeding, resulting in a large increase in yield. The ability analysis is of special importance in cross-pollinated crops like maize as it helps in identifying potential parents that can be used for producing hybrids and synthetics. New molecular tools and techniques can complement traditional methods to allow breeders to tackle priority research areas efficiently. Nepal’s reliance on imported hybrid maize seed and grain increased each year as competitive hybrid cultivars became unavailable within the country. Recently, higher yield gap due to lower productivity, being the major concern in Nepal, single cross hybrids are intervention point. For the countries like Nepal, where achieving higher yield of maize to address self-sufficiency is the nationally prioritized issue, single cross hybrids of maize could be the best way to come up.

Performance of Single Cross Maize (Zea mays L.) Hybrids under Rainfed Middle Hill Environments of Nepal

Performance of Single Cross Maize (Zea mays L.) Hybrids under Rainfed Middle Hill Environments of Nepal

Development of Seed Production Technology of CIMMYT Tropical Single Cross Maize Hybrids

Medium and small seed companies require information on maize parental seed production to make rational choices on what germplasm to introduce into their seed and breeding pipelines. The objective of this study was to generate public data on the appropriate hybrid seed production information of five female lines (T21, T26, T28, T33 and T38) and one line (T10) as a male hybrid parent. The effect of female and male sowing date and sowing density on hybrid seed production characteristics including flowering time, flowering duration, distance between tassel and stigmas and effective seed yield was determined. Recommendations to stagger male and female sowing to achieve flowering synchrony for the hybrid parents were complemented with data of seedling growth stages. The results were similar for T21, T26, T28, and T38; sowing the female and T10 on a row proportion of 4 females:1 male, and on a second date, when the coleoptiles of the female plants are halfway to emerge, sowing the missing male row to complete the 4:2 ratio. T33 is a late flowering line, therefore it is desirable to sow T33 first and T10 five days later, or when the T33 coleoptile begins to emerge. Plant densities did not cause differences in most plant characteristics. Line T21 showed good female parental traits. While this study provides a knowledge framework for seed production technology for these single cross hybrids, data specific to seed production regions need to be generated by seed companies to define the best regimes for hybrid production.

Evaluation of yield and agronomic components of three-way cross maize hybrids under low-light environment

The development and the use of low light tolerant varieties is one of the technologies to overcome the limitations of hybrid maize in the land with the low-light condition. The objectives of the study were to determine the effect of shading/low light intensity on the growth and production of three-way cross maize hybrid, as well to generate hybrid variety that is tolerant to the shade stress condition. The research was conducted under two different environmental conditions, i.e. Screen House environment with 35% of paranet shading condition, and normal environment condition at Indonesian Cereals Research Institute experimental station from July to October 2018. The research was arranged in a Randomized Block Design (RBD) with three replications. The research material consisted of nine three-way crosses (STJ01-STJ09) and two check varieties (Bima-19 and P35). The results indicated that as many as four genotypes performed high yield under 35% shading condition i.e. STJ01, STJ02, STJ06 and STJ07 which yielded 5.60; 6.55; 5.87 and 6.15 t/ha respectively. Correlation analysis indicated various traits have a direct effect on grain yield i.e. ear weight, kernel net weight, ear length, number of kernels per row and kernel weight per ear. As for shading condition, the positive correlations were found for ear weight, ear length, number of kernels per row and kernel weight per ear characters.