Early Maize Genotypes Research Articles

Varietal Evaluation and Clustering of Early Maize Genotypes in Mid-Western Hilly Region of Nepal

Eleven early maize (Zea mays) genotypes were evaluated for their yield and yield component traits at the research block of Regional Agriculture Research Station (RARS) Lumle, Kaski, Nepal during Kharif season of 2016. The experiment was laid out in randomized complete block design (RCBD) with three replications. Results showed that all the studied genotypes differed significantly for grain yield as well as other yield component traits except number of kernel per row. Out of tested genotypes COMPOZ-NIPB, EEYC1, POP-445/POP-446 were three top performer genotypes yielding 6.89, 5.38 and 5.19 t ha-1. Early mid Katamari, Rajahar local, Manakamana-5, EEYC1 were statistically at par with Arun-4(standard check) and will be needed further evaluation and improvement by a selection of desirable traits. Eleven genotypes occupied three different clusters and showed that early maize genotypes suggest considerable genetic diversity among themselves. Genotypes belong to cluster one having the highest yield potentials so need to be further evaluation in different location of mid hill and recommended best variety for that domain.

Agronomic performance and genotypic diversity for morphological traits among early maize genotypes

Detailed information on the genetic diversity between maize germplasm (Zea mays L.) is useful for their systematic and efficient use in breeding programs. Fourteen early maize genotypes were studied to assess their performance and genotypic diversity at Doti, Nepal in 2015. Days to tasseling, days to silking, plant height, ear height, ear length, ear diameter and grain yield were significant among genotypes. Genotype SO3TEY-PO-BM, COMPOL-NIOBP and ACROSS-99402 were found higher yielder with earlier maturity. Days to tasseling (0.85), days to silking (0.82), plant height (0.79), ear length (0.71) and ear diameter (0.66) were found highly heritable traits. Grain yield (0.39) and ear height (0.47) medium and remaining traits showed low heritability. High PCV was observed for grain yield (35.10%), number of plants/plot (34.46%), tesseling silking interval (26.85%), harvested ears/plot (24.45%) and husk cover rating (22.85%) where other traits showed medium to low PCV. Grain yield showed high GCV (21.96%), ear height and husk cover had medium and remaining traits showed low GCV (<10%). Plant height (r₌0.498), harvested plants/plot (r₌0.412), harvested ear/plot (r₌0.762), ear length (r₌0.472) and ear diameter (r₌0.470) showed significant positive correlation with grain yield. The yield can be improved if selection applied in favor of those yield components.

Evaluation of early maize genotypes for grain yield and agromorphological traits

The purpose of this study was to assess the variation on agro-morphological traits and grain yield. A set of 14 early maize genotypes were studied at research field of Regional Agricultural Research Station (RARS), Doti, Nepal in summer seasons of 2015 and 2016. The experiment was carried out in Randomized Complete Block Design (RCBD) with three replications in each year. The variation among genotypes was observed for grain yield and flowering. The genotype SO3TEY-PO-BM produced the highest grain yield (4.33 t/ha) in 2015 whereas Rajahar Local Variety produced the highest grain yield (2.52 t/ha) in 2016. The combined analysis over years showed that Farmer’s variety was found earlier in tasseling (36 days) and silking (39 days), followed by S97TEYGHAYB(3) in tasseling (45 days) and by S97TEYGHAYB(3) and Arun-4 in silking (48 days). EEYC1 produced the highest grain yield (3.17 t/ha), followed by COMPOL-NIBP (3.09 t/ha), SO3TEY-PO-BM (2.90 t/ha), S97TEYGHAYB(3) (2.78 t/ha) and Rajahar Local variety (2.77 t/ha), respectively. The information on variation for the agro-morphological traits among studied early maize genotypes will be helpful to plant breeders in constructing their breeding materials and implementing selection strategies.

Resistance of early maturity maize genotypes to southern corn leaf blight

In order to study the resistance of early maize genotypes to Southern Corn Leaf Blight (SCLB) or Maydis Leaf Blight (MLB), RCBD experiments with 20 inbred lines and hybrids in 2014 and 16 genotypes in 2015 were conducted at Karaj and Sari Stations. Inoculation was carried out with spore suspension using syringe (3ml/each whorl) firstly at 3-4 leaf stage of maize, and then, sorghum grain inoculated with fungus was applied at 6-8 leaf stage in whorl of each plant using the bazooka technique. Evaluation was done on the basis of disease progress at pollination stage and two weeks after pollination stage with scale 0-5. The results of variance analysis and mean comparison showed that there are different reactions among genotypes to disease. In this study, in 2014, 15% genotypes categorized into resistant group, and these were genotypes: KE 77003/10 ? KE 75039, KE 72012/12 ? K1263/1 (KSC 400), and K 2331 ? KE 75039. Among 16 genotypes in 2015, three hybrids - No. 16 with pedigree (KE 76009/311? K 1264/5-1), No. 10 with pedigree (K 2331 ? KE 75039) and No. 9 with pedigree KSC 400 (KE 72012/12 ? K1263/1) - were identified as resistant hybrids that can be a good source of resistance to SCLB.

Grain yield stability of early maize genotypes

The objective of this study was to estimate grain yield stability of early maize genotypes. Five early maize genotypes namely Pool-17, Arun1EV, Arun-4, Arun-2 and Farmer’s variety were evaluated using Randomized Complete Block Design along with three replications at four different locations namely Rampur, Rajahar, Pakhribas and Kabre districts of Nepal during summer seasons of three consecutive years from 2010 to 2012 under farmer’s fields. Genotype and genotype × environment (GGE) biplot was used to identify superior genotype for grain yield and stability pattern. The genotypes Arun-1 EV and Arun-4 were better adapted for Kabre and Pakhribas where as pool-17 for Rajahar environments. The overall findings showed that Arun-1EV was more stable followed by Arun-2 therefore these two varieties can be recommended to farmers for cultivation in both environments.

Performance evaluation of early maize genotypes in far western hills of Nepal

Initial evaluation trial of maize (early) genotypes was carried out at Regional Agricultural Research Station, Doti, Nepal in 2013 and 2014. Total fourteen and fifteen genotypes of early maize were included in initial evaluation experiment of the year 2013 and 2014 respectively. The experiment was laid out in randomized complete block design (RCBD) with three replications in each year. Out of the tested genotypes, SO3TEY/LN, ZM 423 and SO3TEY-FM (ER) identified as promising from statistical analysis over year. All the tested characters were found statistically significant. Similarly, the coordinated varietal trial of maize (early) was also carried out in the same station at 2013 and 2014. Total fourteen genotypes in 2013 and fifteen genotypes in 2015 of maize (early) were included in the experiment. The RCB design was applied and the experiment was replicated three times in every year. ZM 627 and ZM 621/Pool -15 genotypes identified as superior next to Arun-2 from the analysis of two year data. All the tested traits were found statistically significant in over year analysis.Journal of Maize Research and Development (2015) 1(1):106-111DOI: http://dx.doi.org/10.5281/zenodo.34291

Assessing the representativeness and repeatability of testing sites for drought-tolerant maize in West Africa

Badu-Apraku, B., Akinwale, R. O., Obeng-antwi, K., Haruna, A., Kanton, R., Usman, I., Ado, S. G., Coulibaly, N., Yallou, G. C. and Oyekunle, M. 2013. Assessing the representativeness and repeatability of testing sites for drought-tolerant maize in West Africa. Can. J. Plant Sci. 93: 699–714. The selection of suitable breeding and testing sites is crucial to the success of a maize (Zea mays L.) improvement programme. Twelve early-maturing maize cultivars were evaluated for 3 yr at 16 locations in West Africa to determine the representativeness, discriminating ability, and repeatability of the testing sites and to identify core testing sites. Genotype main effect plus genotype by environment interaction (GGE) biplot analysis revealed that Zaria (Nigeria), Nyankpala (Ghana), and Ejura (Ghana) displayed the highest discriminating ability. Two mega-environments were identified. Bagou, Nyankpala, Bagauda, Ikenne, and Mokwa constituted the first mega-environment (ME1); Ejura, Ina and Sotuba represented the second (ME2). The ME1 would be more useful for evaluating early maize genotypes for tolerance to drought than ME2 because locations in ME1 were more strongly correlated to Ikenne (managed drought stress site). Among the test locations, Bagou and Mokwa were found to be closely related to Ikenne in their ranking of the cultivars for drought tolerance; Zaria was the exact opposite, indicating that this was the least suitable location for evaluating genotypes for drought tolerance. Nyankpala and Ikenne were identified as the core testing sites for ME1 and Ejura for ME2. TZE Comp 3 C2F2 was identified as the highest yielding cultivar for ME1 and Syn DTE STR-Y for ME2, indicating that they could be used as check cultivars. Ikenne, Nyankpala, and Ejura had moderately high repeatability. They were closer to the average environment axis of each mega-environment and will be useful for culling unstable genotypes during multi-locational testing. Other sites were less representative and not repeatable and will not be useful for evaluating early maize cultivars for drought tolerance.

Comparative Evaluation of Water Deficit Tolerance Capacity of Extra-early and Early Maize Genotypes under Controlled Conditions

Maize is an important staple food crop in Tropical Africa including Nigeria. However, the production of the crop is constrained by inadequate soil moisture resulting from erratic rainfall distribution. There is therefore the need to breed and select for drought tolerant genotypes for production especially in the southern Guinea savannah ecology responsible for over 60% of maize production in Nigeria. Controlled experiments using potted plants were therefore conducted during the dry periods between November 2007 and April 2008. The study evaluated moisture deficit tolerance capacity of two maize maturity groups, consisting of 15 extra-early and 12 early genotypes along with two local checks, subjected to two moisture levels 25% (stressed) and 100% (unstressed) soil available moisture) determined gravimetrically. Crop establishment parameters (% germination and mean germination time (MGT), morphological growth parameters (number and area of leaves, plant height, flowering characteristics), physiological growth indices (leaf area index, crop growth rate, relative growth rate, net assimilation rate and leaf area ratio) were measured during growth. Yield components (harvest index, shelling percentage and number of kernels per cob) and grain yield were determined at harvest. The data were analyzed using the general model of ANOVA and significant means were separated by the Least Significance Difference (LSD) at 5% probability level. The results showed that there were no appreciable differences between the two maturity groups for most measured parameters. However, across the two groups, crop establishment parameters, morpho-physiological growth parameters, yield components and grain yield were significantly reduced by soil moisture deficit, while flowering characteristics were significantly delayed by soil moisture stress with significant variable genotypic responses. Grain yield reduction due to water stress was significantly related to drought susceptibility index (DSI) of the genotypes in the two maturity groups. Conclusively, whereas extra-early genotypes showed good yield potentials but poor drought tolerance which suggested poor yield stability and therefore may not be suitable for the southern Guinea savanna (SGS) ecology in the event of severe stress. However, early genotypes, though showed lower yield potential, had good yield stability and hence are promising genotypes for the SGS ecology.

Evaluation of the reaction of early maturing maize genotypes to common smut using artificial inoculation

In order to study of the resistance of early maize genotypes, 44 lines, and hybrids in 2008 and 30 genotypes in 2009 in RCBD were conducted at Karaj and Esfahan Stations. All of the ears were inoculated by tip injection method at suitable time. Inoculation was carried out with syringe (3ml/each ear) at silking stage. Evaluation was done on ears 3-4 weeks after inoculation. The results of variance analysis and mean comparison showed that there is a different reaction among material to disease. In this study, after harvesting of ears, the resistance of each genotype was determined based on disease severity index (0-7). Among examined lines in 2008, line no. (41) (KE 77004/1-1-1) was specified as susceptible and no. (28 and 42) (KE 77003/1-8-1) and (37A) as resistant lines. Also among hybrids, K SC 400 was identified as resistant hybrid. Also, among lines in 2009, line no. (29) (KE77004/1-1-1) was specified as susceptible and line no. (27) (KE77005/4) as resistant line respectively. Among hybrids, hybrid no. (9) (KE77006/3 ?K1263/1) evaluated as resistant hybrid.