Kernel Row Number Research Articles

Agronomic performance and genetic diversity of newly developed S4 temperate and tropical sweet corn lines

This study aims to evaluate agronomic traits and genetic diversity through correlation analysis, principal component analysis, and cluster analysis on 20 agronomic traits of 16 S4 tropical sweet corn lines (NG01-NGO16) and 4 S4 temperate lines (NGO17-NGO20) developed from varieties imported from Thailand, China, Japan, and the USA along with 3 inbred check lines viz., SW1 (sweet, yellow), D181 (sweet, white) and UV10 (sweet, purple). The field experiment was arranged in a randomised complete block design with 3 replicates in Hanoi, in the autumn-winter crop 2022 to evaluate twenty agronomic traits, divided into 4 groups viz., 5 growth traits, 7 morphological traits, 7 yield traits, and 1 quality trait. Correlation analysis showed that the single plant yield was positively correlated at p<0.01 with the number of kernels per row 0.61, the number of kernel rows per ear 0.57, and positively correlated at p<0.05 with ear diameter 0.47 and ear length 0.45. Twenty traits were dimensionally reduced to 3 main principal components contributing 66.8% of total phenotypic variation in which growth duration, plant height, ear height, leaf angle, number of kernels row per ear, number of kernels per row, 1000-grain weight, single plant yield and total soluble solids can be used to evaluate the differences of sweet corn lines. Cluster analysis based on principal components on 20 agronomic traits classified 20 sweetcorn lines into 3 main groups. This study provided useful information on phenotypic diversity and valuable sweetcorn genetic resources for breeding programs on speciality corn in Vietnam.

Eco-geographic Survey, In-situ Characterization and Spatial Analysis of Phenotypic Traits Diversity among the Maize Landraces Collected from Chhattisgarh

Exploration and germplasm collection expedition undertaken in the three districts of Chhattisgarh state in the present study resulted in the collection of 43 diverse local maize genotypes. The collected accessions were characterized in-situ on a farmer’s field for six ear and seed-specific quantitative characters and the recorded data was analyzed for quantification and analysis of the genetic variability among the accessions. Significant variability was recorded in all the studied traits viz. ear length (7.33–26.67 cm), ear girth(8.00–16.33 cm), number of kernel rows per ear (8-18), number of kernels per ear row (12.67–45.33), ear weight (25.45–204.88 g) and 100 kernel weight (9.74–38.66 g). The first three components explained 99.61% of the total variation; the first principal component represented 97.33%. Cluster analysis based on Euclidean distances classified 43 maize genotypes into five clusters with clustering together of 9, 18, 13, 2 and 1 accessions. Geo-referencing analysis of recorded data was done using DIVA-GIS software. The diversity pattern of maize germplasm accessions revealed by the grid maps confirmed the existence of considerable genetic diversity for all the six quantitative traits in the surveyed area also discussed in this study.

Effects of Crop Geometry and Split Nitrogen Application on Spring Maize Growth, Yield Components and Yield in Digam, Gulmi, Nepal

Maize (Zea mays L.) is a heavy nutrient feeder that needs optimum spacing and appropriate time to apply nitrogen to get maximum yield. A field study was carried out at Digam, Gulmi, from February to June 2022 to examine the impact of crop geometry and split application of nitrogen on spring maize in two factorial randomized complete block design (RCBD) with four replications. Factor A was the split application of nitrogen; (120 kg ha-1N at the time of sowing) and (60 kg ha-1N at the time of sowing + 30 kg ha-1N at knee height stage + 30 kg ha-1N before tasseling stage) and factor B included the three levels of spacing (75 cm x 25 cm, 60 cm x 25 cm and 50 cm x 25 cm). Plant height , stem girth , leaf number, cob girth, thousand grain weight, number of kernel rows per ear, number of kernels per row, and grain yield (3.45 MT ha-1) were all highest for treatment (60 kg ha-1N at sowing + 30 kg ha-1N at knee height + 30 kg ha-1N before tasseling). Likewise, plant height, leaf area index, cob length, cob girth, cob weight, thousand grain weight, number of kernels per row, grain yield (3.04 MT ha-1) and harvest index were highest in plant spaced at (75 cm x 25 cm), while the number of kernel rows per ear was highest in plants spaced at (60 cm x 25 cm). The lowest value of all parameters was found in plants at treatments; (120 kg ha-1N at the time of sowing) and (50 cm x 25cm). Similarly, the treatment (60 kg ha-1N at the time of sowing + 30 kg ha-1N at knee height stage + 30 kg ha-1N before tasseling stage) combined with spacing of (60cm x 25cm) was found to have a significant effect on grain yield (3.99 MT ha-1) which was statistically at par to the treatments, (60 kg ha-1 N at the time of sowing + 30 kg ha-1 N at knee height stage + 30 kg ha-1 N before tasseling stage) combined with spacing of (75 cm x 25 cm) (3.95 MT ha-1 ) . Thus, for the optimum and sustainable production of the spring maize, crop geometry of (75 cm x 25 cm) or (60 cm x 25 cm) can be recommended with three splits application of nitrogen at Digam, Gulmi.

Phosphorus partitioning contribute to phosphorus use efficiency during grain filling in Zea mays.

Lower phosphorus (P) availability limits crop productivity in agroecosystems. The remobilization of P from the source to the sink organs plays an important role in enhancing the P-utilization efficiency of crops. During the grain filling stage, phosphorus flow to the developing grains, the primary sink, determines crop yield. However, the specific contributions of different organs to grain P throughout the post-silking period in maize remain unclear. In our study, three maize inbred lines (CIMBL89, Ji846, and CML118) with contrasting P statuses were selected and grown in a field with high P (HP, 150 kg ha-1 P2O5) and low P (LP, 0 kg ha-1 P2O5) conditions. The grain yield of CIMBL89 was 69% and 169% greater under HP supply, and 83% and 309% greater than those of Ji846 and CML118 under LP supply, respectively. The ear length, ear diameter, and kernel row number of CML118 were lower than those of CIMBL89 and Ji846 under HP conditions. Most of the P (87%) in the grains of CIMBL89 came from P uptake at the LP supply, while almost all P (95%) came from P remobilization in various organs at the HP supply after silking. In contrast, 91% of the P found in the grain of CML118 came from P remobilization under LP supply, while 76% came from P uptake under HP supply after silking. In conclusion, our findings suggest that CIMBL89, with greater P acquisition efficiency, contributes to grain formation and production during the post-silking period under LP conditions. Additionally, CIMBL89 can fully remobilize P and avoid the extravagant absorption of P in P-sufficient soil, which sets it apart from Ji846 and CML118.

Accessing the efficacy of different doses of phosphorus on growth and yield of spring maize (Zea mays L.) at Gulmi, Nepal

Phosphorus is one of the most important crop-limiting elements which plays a crucial role in the growth as well as the development of the plant. To meet the crop need and to obtain the efficiency of fertilizer they should be applied in appropriate doses. Thus, an experiment including six different doses of phosphorus as a treatment (0, 20, 40, 60, 80, and 100) kgha-1 was designed to identify the optimum dose of phosphorus for better growth and yield of spring maize. The study was carried out according to one factorial RCBD with four replications of six treatments at Satyawati rural municipality, Khaireni, Gulmi from February-June 2022. Maize seeds (Arun-2) treated with Bavistin were sown by maintaining a spacing of 75*25 cm2. Different observations like biometrical, phenological as well as yield-attributing characters were recorded. The results showed that the different doses of phosphorus significantly affected the recorded parameters. The plant height was found highest (164.92cm) with 100kg P2O5 ha-1 which was statistically similar to the plant height (155.57cm) obtained at 80kg P2O5 ha-1. The longest days to silking and tasseling were found at 0 kg P2O5 ha-1. Likewise, cob length (23.05cm), number of grains per kernel (26.76), and shelling percentage (74.48%) were highest in plants with 100kg P2O5 ha-1and number of kernel row per cob (15.19), number of grains per cob (406.22) 1 and grain yield (6203.29kg ha-1) was highest in plants with 80 kg P2O5 ha-1. The maximum harvest index percentage (38.13%) was obtained in 60 kg P2O5 ha-1. There was no significant variation of treatment on thousand-grain weight. This research showed that the treatment of 80kg P2O5 ha-1 was found to boost the yield of maize by enhancing the growth and yield attributes of maize. Thus, for a better and improved yield of maize 80 kg P2O5 h-1 is recommended in Gulmi.

Agronomic Performance of IPB Maize Hybrids and Combining Ability of the Lines

Maize is a significant food crop consumed in numerous countries worldwide. Increasing the yield potential of maize can be achieved through the breeding of high-yielding hybrid varieties. The objectives of this study were to assess the performance of hybrid means and parent combining ability for grain yield and other agronomic traits using a line x tester mating design. The study took place at the Gunung Gede Experimental Station of IPB University, Bogor, from June to October 2022. The experiment was conducted using a randomized complete block design with a single genotype factor and three replications. Twenty-two hybrids were utilized as genetic materials, including 20 hybrid candidates and two check varieties. Six maize lines (H1, L26, Nei, P2B, and P42) were employed as line parents, while L15 and P10 were used as tester parents in the line x tester analysis. The neighbor-joining tree analysis indicated that the female parent has a significant influence on the agronomic and yield performance of the hybrids. Correlation analysis revealed that the yield is more strongly influenced by ear diameter rather than ear length, and it is more affected by the number of kernel rows than the number of kernels per row. Three selected hybrids with favorable traits were Nei x B1, L15 x L26, and L26 x P10. The parent L26 demonstrated relatively good general combining ability for yield and may be considered for future maize breeding program.

Germplasm collection – valuable resources of variability for plant and ear traits in maize breeding

Maize is one of the most important crops, both worldwide and in Romania, and preserving the diversity of the biological material used in the breeding of this plant is of particular importance. The Agricultural Research and Development Station (ARDS) Turda, Romania, inbred lines collection includes both its own genotypes and some obtained as a result of germplasm exchanges with other institutions in the country or abroad. In the present study, 575 lines created at Turda were analysed regarding some traits of the plant (plant height, ear height, total number of leaves, number of tassel branches) and the ear (ear length and weight, number of kernel rows and number of kernels/row). The biological material used in this study shows a great diversity: a medium or high variability coefficient was identified for several of the traits analysed (number of tassel branches, ear height, ear height). Frequency histograms were made for the studied lines, for plant and ear traits. A great variability also was observed in the colours of the anther and silk, but also for kernel type and colour and cob colour.

Gene expression and expression quantitative trait locianalyses uncover natural variations underlying the improvement of important agronomic traits during modern maize breeding.

Maize (Zea mays L.) is a major staple crop worldwide, and during modern maize breeding, cultivars with increased tolerance to high-density planting and higher yield per plant have contributed significantly to the increased yield per unit land area. Systematically identifying key agronomic traits and their associated genomic changes during modern maize breeding remains a significant challenge because of the complexity of genetic regulation and the interactions of the various agronomic traits, with most of them being controlled by numerous small-effect quantitative trait loci (QTLs). Here, we performed phenotypic and gene expression analyses for a set of 137 elite inbred lines of maize from different breeding eras in China. We found four yield-related traits are significantly improved during modern maize breeding. Through gene-clustering analyses, we identified four groups of expressed genes with distinct trends of expression pattern change across the historical breeding eras. In combination with weighted gene co-expression network analysis, we identified several candidate genes regulating various plant architecture- and yield-related agronomic traits, such as ZmARF16, ZmARF34, ZmTCP40, ZmPIN7, ZmPYL10, ZmJMJ10, ZmARF1, ZmSWEET15b, ZmGLN6 and Zm00001d019150. Further, by combining expression quantitative trait loci (eQTLs) analyses, correlation coefficient analyses and population genetics, we identified a set of candidate genes that might have been under selection and contributed to the genetic improvement of various agronomic traits during modern maize breeding, including a number of known key regulators of plant architecture, flowering time and yield-related traits, such as ZmPIF3.3, ZAG1, ZFL2 and ZmBES1. Lastly, we validated the functional variations in GL15, ZmPHYB2 and ZmPYL10 that influence kernel row number, flowering time, plant height and ear height, respectively. Our results demonstrates the effectiveness of our combined approaches for uncovering key candidate regulatory genes and functional variation underlying the improvement of important agronomic traits during modern maize breeding, and provide a valuable genetic resource for the molecular breeding of maize cultivars with tolerance for high-density planting.

Evaluation of agronomic and grain yield of elite hybrids maize in south-western Nigeria

The poor grain yield of maize obtained among Nigeria small holder farmers has been an issue leading to the continuous development of maize genotypes with the aim of improving yield in the farmers’ in order to improve the household income. Evaluation of the agronomic and grain yield of some of th4 elite hybrids maize was conducted with the aim to determine their performance in order to ascertain their suitability for the south-western agro-ecology of Nigeria. Three elites hybrid maize genotypes groups made up of 30 entries of early white and yellow maize (Elite 1), 36 entries of early white maize, 36 entries of late/intermediate maturing (Elite 3) and 24 entries of open pollinated (OPV) were evaluated at the teaching and research farm of Obafemi Awolowo University, Ile-Ife, Nigeria in two late cropping seasons of 2019 to 2020. The treatments were laid out in a randomized incomplete block design (lattice design) with three replications in each season. Data were obtained on agronomic (plant height, ear height, stem lodge, root lodge plant aspect, ear aspect and husk cover), grain yield and yield components (ear length, ear girth, number of kernel rows per ear and number of kernels per row). It was noted that 6 entries from early maturing white and yellow elites (Elite 1), two from early maturing white elites (Elite 2), one from late/ intermediate elites (Elite 3) and one from the open pollinated varieties (OPV) genotypes showed superior agronomic character while one of Elite 1 and 9 of Elite 2 genotypes showed most superior yield character across seasons. Genotypes EWH114(E1), EWH110(E1), EYTWH-9(E2) were observed to be stable and showed superior performance in agronomic character and grain yield. These genotypes are to be advocated for growth and grain yield.

Designed and validated novel allele-specific primer to differentiate Kernel Row Number (KRN) in tropical field corn.

Kernel row number (KRN) is an important yield component trait with a direct impact on the productivity of maize. The variability in KRN is influenced by the inflorescence meristem size, which is determined by the CLAVATA-WUSCHEL pathway. A CLAVATA receptor-like protein, encoded by the FASCIATED EAR2 (fea2gene), enhances the growth of inflorescence meristem and is thus involved in the determination of KRN. The amplicon sequencing-based method was employed to dissect the allelic variation of the fea2 gene in tropical field corn. Amplicon-based sequencing of AI 535 (Low KRN) and AI 536 (High KRN) was undertaken for the gene fea 2 gene that codes for KRN in maize. Upon multiple sequence alignment of both sequences, A to T transversion at the 1311 position was noticed between Low KRN and High KRN genotypes resulting in different allelic forms of a fea2 gene in tropical maize. An allele-specific primer 1311 fea2.1 was designed and validated that can differentiate High and Low KRN genotypes. Maize has high variability for KRN and is exemplified by the wide values ranging from 8-26 KRN in the maize germpalsm. The sequence-based approach of SNP detection through the use of a specific primer facilitated the detection of variation present in the target trait. This makes it possible to capture these variations in the early generation. In the study, the PCR-based differentiation method described for the identification of desirable high KRN genotypes would augment the breeding programs for improving the productivity of field corn.

Performance evaluation and genetic parameters estimation of multi-companies maize hybrids in Lamahi Dang, Nepal

Selection, a basic and crucial step of breeding, can be made efficient through the estimates of genetic parameters. Ten multi-company’s maize hybrids and two Nepalese maize hybrids were used as standard checks and evaluated in a randomized complete block design with three replications. Analysis of variance for different characters revealed significant differences for most of the characters among the genotypes used. The phenotypic coefficient of variation (PCV) was observed to be higher than the genotypic coefficient of variation (GCV) for all traits studied suggesting those traits interacted with the environment. The traits under study showed a wide range of heritability estimates (24%–90%). Among the characters, highest heritability and genetic advance were recorded for grain yield. Path coefficient analysis showed that the plant height, ear weight, number of kernel rows cob−1 and number of kernel row−1 and thousand kernel weight showed positive direct effect on grain yield. Ear weight and number of kernels row−1 had significant and positive correlation with grain yield. Therefore, much attention should be given to ear weight and number of kernels row−1 as these traits are helpful for indirect selection. Star 9, 10V10, and Shrestha were observed as superior and yielded higher than Rampur Hybrid 10 and Khumal Hybrid 2 in terms of grain yield.

QTL mapping identifies novel major loci for kernel row number-associated ear fasciation, ear prolificacy and tillering in maize (Zea mays L.).

Maize ear fasciation originates from excessive or abnormal proliferation of the ear meristem and usually manifests as flattened multiple-tipped ear and/or disordered kernel arrangement. Ear prolificacy expresses as multiple ears per plant or per node. Both ear fasciation and prolificacy can affect grain yield. The genetic control of the two traits was studied using two recombinant inbred line populations (B73 × Lo1016 and Lo964 × Lo1016) with Lo1016 and Lo964 as donors of ear fasciation and prolificacy, respectively. Ear fasciation-related traits, number of kernel rows (KRN), ear prolificacy and number of tillers were phenotyped in multi-year field experiments. Ear fasciation traits and KRN showed relatively high heritability (h 2 > 0.5) except ratio of ear diameters. For all ear fasciation-related traits, fasciation level positively correlated with KRN (0.30 ≤ r ≤ 0.68). Prolificacy and tillering were not correlated and their h 2 ranged from 0.41 to 0.78. QTL mapping identified four QTLs for ear fasciation, on chromosomes 1 (two QTLs), 5 and 7, the latter two overlapping with QTLs for number of kernel rows. Notably, at these QTLs, the Lo1016 alleles increased both ear fasciation and KRN across populations, thus showing potential breeding applicability. Four and five non-overlapping QTLs were mapped for ear prolificacy and tillering, respectively. Two ear fasciation QTLs, qFas1.2 and qFas7, overlapped with fasciation QTLs mapped in other studies and spanned compact plant2 and ramosa1 candidate genes. Our study identified novel ear fasciation loci and alleles positively affecting grain yield components, and ear prolificacy and tillering loci which are unexpectedly still segregating in elite maize materials, contributing useful information for genomics-assisted breeding programs.

Integrating BSA-Seq with RNA-Seq Reveals a Novel Fasciated Ear5 Mutant in Maize

Increasing grain yield is required to meet the rapidly expanding demands for food, feed, and fuel. Inflorescence meristems are central to plant growth and development. However, the question concerning whether inflorescence development can be regulated to improve grain yield remains unclear. Here, we describe a naturally occurring single recessive mutation called fea5 that can increase grain yield in maize. Using bulk segregant analysis sequencing (BSA-seq), the candidate region was initially mapped to a large region on chromosome 4 (4.68 Mb-11.26 Mb). Transcriptome sequencing (RNA-seq) revealed a total of 1246 differentially expressed genes (DEGs), of which 835 were up-regulated and 411 were down-regulated. Further analysis revealed the enrichment of DEGs in phytohormone signal transduction. Consistently, phytohormone profiling indicated that auxin (IAA), jasmonic acid (JA), ethylene (ETH), and cytokinin (CK) levels increased significantly, whereas the gibberellin (GA) level decreased significantly in fea5. By integrating BSA-seq with RNA-seq, we identified Zm00001d048841 as the most likely candidate gene. Our results provide valuable insight into this new germplasm resource and the molecular mechanism underlying fasciated ears that produce a higher kernel row number in maize.

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.

Correlation and Path Analysis in Elite Maize (Zea mays L.) Lines

Aim: To study the association between characters through correlation and path analysis for 30 elite maize lines
 Study Design: Randomized Block Design with three replications.
 Place and Duration of Study: The experiment was conducted at Seed Research and Technology Centre Rabi 2020-21.
 Methodology: Character association studies will help to assess the relationship between the yield and its contributing traits for enhancing efficiency selection. Because of this, the present research work was carried out to assess the correlation coefficient and path analysis among thirty maize inbred lines for eighteen yield, yield contributing characters and seedling vigour traits in maize (Zea mays L.).
 Results: Correlation studies revealed that plant height (0.3566**), ear height (0.2135**), ear length (0.3505**), ear diameter (0.4973**), number of kernel rows (0.3471**), 100-seed weight (0.5359**), cob yield per plant (0.9883**) and seed vigour index-2 (0.3412**) were significant and positively correlated with the grain yield per plant. Path analysis showed that cob yield per plant had the highest positive direct effect on grain yield per plant followed by shelling percentage (0.0094), seed vigour index -1 (0.0131), seed vigour index-2 (0.0125), 100 seed weight (0.0122), days to tasseling (0.0108), germination first count (0.0094), speed of germination (0.0060), number of kernels per row (0.0058), ear diameter (0.0057) suggesting that grain yield could be indirectly enhanced by the selection of these characters.

Evaluation of performance and genetic parameters in quality protein maize genotypes

Quality protein maize (QPM) contains opaque-2 mutant genes that increases lysine and tryptophan level which are not normally found in maize. The objective of this study was to evaluate the performance of QPM genotype based on their yield, yield attributing and other relevant characteristics. A varietal trial on QPM was conducted in the research field of Lamahi municipality-3, Dang, Nepal from February to June 2021. This experiment was performed in Randomized Complete Block Design with three replications. Thirteen genotypes of QPM and one standard check (Poshilo Makai-2) were evaluated. Each genotype was assigned an area of 3m × 3m with a net plot area of 452.5m2 per block. Analysis of variance revealed significant data for the most of the genotypes. Four genotypes Rampur-S13FQ-02 Rampur-SO3FQ-02, Rampur-S13FQ010 and Rampur-S13FQ-08 were found superior with a yield of 4.32 t/ha, 3.97 t/ha, 3.89 t/ha, 3.63 t/ha respectively in comparison to the standard check Poshilo makai-2 (2.66 t/ha). Significant and positive correlation were observed for the ear length, ear diameter, number of kernels per ear, number of kernel row per ear, ear weight whereas negative for ear aspect with grain yield was observed. Ear weight without husk had the highest contribution to grain yield. For all observed traits, the coefficient of phenotypic variation (PCV) was found to be higher than that of genotypic coefficient of variation (GCV). The highest GCV, PCV, genetic advance and heritability were observed in ear aspect, thousand grain weight, ear height, plant height respectively. As a result, breeding programs can be further improved by selecting these traits.

Comparative Analysis of Genetic Parameters for Yield and Yield Attributing Traits in Kharif and Rabi Maize (Zea mays L.)

The present investigation was carried out to assess the genetic variability parameters, correlation and path analysis in 30 maize genotypes for 15 quantitative traits in rabi and kharif seasons during 2019-20 at Sam Higginbottom University of Agriculture Technology and Sciences, Uttar Pradesh in Randomized Block Design replicated thrice. ANOVA for all quantitative characters revealed that treatment differences were highly significant in both the seasons under study at 1% level except for number of kernel rows per cob in Kharif season. Genotypes CML-193-1, CM-137 and CML-K5/ATM depicted highest grain yield in both the environments. The values of PCV were higher than GCV values for all the characters in both the seasons and large difference between the values of PCV and GCV of characters like grain yield per plant, cob weight, shank weight and anthesis-silking interval under both seasons, indicated that environmental factors significantly influenced the expression of these traits. All the traits studied had higher heritability, genetic advance at 5% selection intensity and genetic advance as percent of mean in rabi season than in kharif season, high expected genetic advance coupled with high heritability was observed for grain yield per plant, cob weight, plant height and ear height indicating the presence of large proportion of additive genetic action deciding these traits. Correlation and path coefficient studies suggest that selection based on characters cob girth, number of kernel rows per cob, cob weight and 100 kernel weight had positive correlation and direct effects with grain yield per plant. Therefore, it is concluded that effective selection must be attempted for these traits which would help in improvement of grain yield in maize genotypes suitable for different environments.

Comparative transcriptomics analysis at the key stage of maize ear development dissect heterosis.

Important traits related to maize (Zea mays L.) grain yield, such as kernel row number, ear length, kernel number per row, are determined during the development of female inflorescence. There is a significant positive correlation between yield component and the activity of inflorescence meristem (IM). To find the key stage of heterosis in the development of the ear, immature ears (from the IM stage until the end of the floral meristem [FM] stage) of Yudan888 and its parent lines were sampled to assay phenotype and for comparative transcriptomics analysis. The immature ear length of Yudan888 at the IM stage fitted an additive (mid-parental) model, but it showed high parental dominance at the spikelet-pair meristem (SPM) stage. Comparative analysis of transcriptomes suggested significant differences between additive and nonadditive expression patterns for different developmental stages. The number of distinct maternal or paternal genes (DMP) (genes expressed only in one parental line and their hybrid but silenced in another line) was greater than ABF1 (genes expressed in both parental lines but silenced in hybrid) at each stage. Gene Ontology (GO) enrichment suggested that the cell redox homeostasis genes with overdominance expression patterns in hybrids have an important contribution to heterosis. According to our research, anear lengthheterosis networkwas established. The discovery of the inflection point for ear length heterosis allows us for inferring that the transition state of IM to SPM may be the starting point of ear length heterosis. These findings improved the understanding of maize ear lengthheterosis.

Studies on Character Association and Path Coefficient Analysis for Grain Yield and Its Contributing Characters in Maize (Zea mays L.)

The present investigation was undertaken at Agricultural Research Station, Tornala, Telangana, India during rabi, 2019-20 and kharif, 2020 to study the cause of association and direct & indirect effects for yield and its contributing traits in fifteen hybrids along with their eight parents and three checks of maize. The experiment was conducted in Randomised Block design with two replications. Correlation analysis revealed that, grain yield was found to be significant & positively correlated with these characters viz., ear height, ear length, number of kernels row-1, ear diameter, plant height, number of kernel rows, 100 kernel weight, shelling % and significant & negatively correlated with characters days to 50% tasseling and days to 50% silking. Path coefficient analysis revealed that the characters days to 50% tasseling exhibited the largest direct effect on grain yield followed by number of kernels per row, 100 kernel weight and ear diameter. The traits like no. of kernels/row, ear diameter and 100 kernel weight displayed positive significant correlation as well as positive direct effect on yield. Hence, due emphasis should be given to these traits in formulating selection criteria to bring high yield.

Correlation and Path Coefficient Analysis for Grain Yield Components in Maize (Zea mays L.)

In the present study, "Correlation and path coefficient analysis for grain yield components in maize (Zea mays L.)," the aim was to estimate genetic variability, genetic advance, correlation, and direct and indirect effects of yield contributing traits on yield. According to the analysis of variance, all traits exist. Hence, the data on all the 16 traits which showed significant differences among the entries were subjected to further statistical analysis. GP-184 had the shortest grain yield per plant in comparison to other genotypes, whereas GP-87 had the highest grain yield. Grain yield per plant, ear height, plant height, and cob weight exhibited the highest genotypic coefficient of variation. Cob weight. Among the traits, grain yield per plant, ear height, plant height, cob weight, and cob length showed a higher phenotypic coefficient of variation. The traits ear height, grain yield per plant, plant height, number of cobs per plant, cob length, number of kernels per row, cob weight, number of kernels per row per cob, anthesis to silking interval, shank weight, and days to 50% silking exhibited the highest heritability. Plant height, grain yield per plant, ear height, and cob weight were traits that showed higher genetic advances. These traits included grain yield per plant, ear height, plant height, cob weight, cob length, number of cobs per plant, tassel length, number of kernels per row, number of kernel rows per cob, 100-kernel weight, anthesis to silking interval, cob girth, and shank weight that showed higher genetic advance as a percent mean. The correlation coefficient indicates there is a significant positive correlation between grain yield and cob weight, number of cobs per plant, number of kernels per row, number of kernel rows per cob, 100 kernel weight, cob length, cob girth, plant height, ear height, shank weight, and tassel length at the phenotypic level. Grain yield per plant significantly positive correlation with cob weight, number of cobs per plant, number of kernels per row, number of kernel row per cob, 100 kernel weight, cob length, cob girth, plant height, shank weight, ear height, tassel length at the genotypic level the phenotypic level, the traits cob weight, 100 kernel weight, and plant height had the greatest direct impact on grain yield per plant. The traits were cob weight, number of kernel row per cob, 100 kernel weight showed higher direct effect on grain yield per plant at genotypic level.