Breeding maize (Zea mays L.) for stable production and adaptability poses a significant challenge because of the vital role of genotype and environment interactions. The presented study aimed to elucidate the maize hybrids’ response, estimating the genetic parameters and trait associations, to identify the stable hybrids under optimum and suboptimum conditions. The conducted experiment used an augmented randomized complete block design, where check varieties had three replications across three blocks. The combined analysis of variance revealed that genotype-by-environment interactions significantly affected the grain yield and most of the traits. The average grain yield under the suboptimum environment was lower than the optimum environment. Genetic variability belonged to the high category, whereas the heritability was in the range of moderate to high for most traits. Grain yield appeared notably correlated with plant and ear height, stay green, kernels per row, and anthesis-silking interval. The maize hybrids G02, G06, G07, G08, G09, and G10 emerged as stable based on stability statistics, while hybrids G06, G08, G09, and G10 were also considered stable based on the GGE analysis. The identified genetic variability, trait association, and stable maize hybrids could be beneficial in future maize breeding programs for further improvement in grain yield.

Keywords: Maize (Z. mays L.), optimum and suboptimum abiotic conditions, G × E interactions, hybrids’ response, genetic variability, traits association, yield-related traits

Key findings: Information on genotype by environment interaction effects, heritability, and trait association may be useful for selecting promising maize (Z. mays L.) hybrids. Six maize hybrids were identified as stable hybrids based on parametric and non-parametric stability.

Heterosis and combining ability are reputable fundamental breeding tools in assessing the performance of hybrids and the extent of the parents’ combining ability. In the present study, evaluating 11 yield-attributing traits of 15 hybrids of the field mustard (Brassica rapa L.) helped estimate the magnitude and direction of combining ability and heterotic effects. The hybrids evolved from six diverse parents following a half-diallel mating scheme at the research farm of Sher-e-Bangla Agricultural University. The GCA effects showed that parents BARI-12, BARI-17, and BINA-10 for early maturity and plant height, while the parents BARI-6, BARI-14, and Maghi can be favorable as potential parents for yield-attributing traits. The hybrids BARI-6 × BARI-12 and BARI-12 × BINA-10 exhibited maximum negative SCA and heterotic effects for early maturity, and the hybrids BARI-12 × BARI-17 and BARI-14 × Maghi had the highest negative effects for plant height. Moreover, for yield and yield-contributing traits, hybrids BARI-6 × BARI-14, BARI-14 × Maghi, and BARI-17 × Maghi manifested higher SCA and heterotic effects than the other hybrids. The phylogeny and clustering analysis showed the developed hybrids have quite diversity, having been positioned in different clades. It suggests breeding superior recombinants could be effective from the segregating populations of hybrids.

Keywords: Mustard (B. rapa L.), combining ability, heterosis, genetic distance, early maturity, highyielding hybrids

Key findings: Promising findings indicate the early maturity and short-stature phenotypes incurred controlled by additive genetic effects. In general, non-additive gene action regulates the inheritance of most of the yield-attributing traits in B. rapa L. Overall, the hybrids, viz., BARI-6 × BARI-14, BARI-12 × BARI-17, and BARI-17 × Maghi could become potential lines in B. rapa L. breeding programs.

The assessment of the inheritance and heritability of quantitative traits in 36 hybrid populations of barley (Hordeum vulgare L.) under greenhouse conditions was the presented study’s focus. Results revealed the predominance of additive gene action for controlling the studied traits, indicating the possible effective selection in the F2 generation. For selection in early generation, the most accessible traits were plant height, ear length, and grains per ear, with their variability due to an additive gene action, which is more helpful to conduct targeted breeding work. Barley hybrid populations’ detection with the highest heritability coefficients for specific traits have shown in Rihane x Saule (for five traits) and three hybrids Syr Aruy x Donetskiy 8, Syr Aruy x Odesskiy 100, and Harmal x Saule (for four traits). This suggests selecting the highly productive hybrids adapted to stressful environmental conditions.

Keywords: Barley (H. vulgare L.), hybrid populations, breeding, selection, inheritance, heritability, additive gene action

Key findings: By studying barley (H. vulgare L.) hybrid populations under artificial climate conditions, the genetic criteria and intensive selection can be helpful for a comprehensive assessment of breeding material based on economic traits.

With climate change and global warming, a specific place is necessary for the selection of facultative soft wheat, as this crop has increased plasticity and adaptability to environmental conditions compared with the winter and spring wheat. In facultative wheat breeding, the use of classical methods can be via standard selection and sowing of hybrid populations alternately in autumn and spring. Facultative hybrid populations comprised facultative x facultative genotypes, winter x spring cultivars, and spring x winter cultivars. The duration of ‘germination-earing’ can serve as an additional indicator for selection and types of crossing: facultative x winter cultivars and spring x winter cultivars were the decision in breeding for better productivity. In seed production and to preserve the economically valuable properties of a facultative cultivar, it is necessary to use the ‘halves’ method. Facultative wheat is superior to winter sowing and has low sensitivity to vernalization but highly sensitive to photoperiod. However, few past studies carried out on facultative wheat breeding used modern biological methods and techniques. The production of facultative wheat is mainly a task carried out by the Krasnodar Territory (Russia) and the Republic of Kazakhstan. In 2023, in the south and southeast of the Republic, the area sown with facultative wheat of the Kazakhstanskaya 10 variety amounted to 28,953.8 hectares.

Keywords: Facultative soft wheat, selection, photoperiodism, molecular markers, production

Key findings: This review article interprets the facts of facultative breeding materials obtained through classical selection and the cultivars developed in Russia, Armenia, Georgia, Kyrgyzstan, Turkey, New Zealand, and in South-East Kazakhstan, actively involved in production

An association of biotic and abiotic stress resistance has existed with modifying the genetic makeup of plant cells, and as a result, variations occur in some physiological and biochemical processes. Relatedly, the collection of bread wheat (Triticum aestivum L.) germplasm and its assessment through morphological, genetic, and physiological parameters are practically significant. Studying the influence of the genotype-environment on the physiological and quantitative characteristics of bread wheat germplasm in Uzbekistan resulted in the environment influencing the wheat genotypes, with a hydrothermal coefficient of Ij = 1.43 in 2017. It gave the average grain yield from all the wheat nurseries at 6.84 t/ha. Meanwhile, in 2019, the hydrothermal coefficient was Ij = 0.69 with a grain yield of 6.77 t/ha. However, when the hydrothermal coefficient decreased to a negative value (Ij = -2.8), the average yield decreased to 6.48 t/ha. The identification of wheat genotypes succeeded according to environmental plasticity (bi) and stability coefficient (Si2) indicators, i.e., K-64 (bi = 0.5, Si2 = 1.8), K-74 (bi = 0.7, Si2 = 1.9), and genotype K-100 (bi = 0.4, Si2 = 0.9).

Keywords: Bread wheat (T. aestivum L.), genetic attributes, morphological traits, physiological processes, leaf, carotenoid, grain yield

Key findings: Regression analysis showed a one-mg increase in total chlorophyll content raised the productivity of 50 selected bread wheats (T. aestivum L.) genotypes by 12%. The three-year average of total chlorophyll ranged from 3.34 to 2.03 mg/g, with productivity also significantly reduced in wheat genotypes with low chlorophyll content.

A field experiment on olive (Olea europaea L.) saplings examined the influence of the Acadian seaweed extract and organic humic acid, carried out from March to November 2022 in an orchard located in Jazirah, Ramadi Region, Iraq. The study aimed to determine effects of foliar application of seaweed extract Acadian and organic fertilizer humic acid with concentrations of 0, 250, 500, 750, and 1000 mg L^-1 on olive saplings’ foliage. Results showed spraying coefficients with individual treatments of Acadian and Humic fertilizers at the concentration of 1000 mg L^-1 significantly outperformed most studied traits. These provided the highest averages for main stem height (92.93 and 98.67 cm), main stem diameter (6.193 and 6.060 mm), leaf number (479.2 and 397.7), leaf area (602.4 and 455.1 cm²), leaf chlorophyll content (73.60 and 75.73 SPAD), dry weight of vegetative parts (97.87 and 91.40 g), and root system (23.13 and 18.07 g), respectively. The interactions of both factors at 1000 mg L^-1 concentration were superior on olive saplings for the main stem height (131.00 cm), main stem diameter (7.067 mm), leaves seedling^-1 (670.3), leaf area (689.0 cm²), leaf chlorophyll content (83.67 SPAD), dry weight of vegetative parts (122.33 g), and root system (28.33 g). The study concluded, based on results, that foliar fertilization, whether with biological or organic fertilizer, contributes positively and effectively to improving olive seedlings’ growth.

Keywords: Olive (O. europaea L.), Acadian seaweed extract, organic Humic, nutrients, vegetative, root system

Key findings: The results revealed a greater improvement in growth and morphological traits of olive (O. europaea L.) saplings with foliar application of organic fertilizers at a concentration of 1000 mg L^-1.

A biological experiment proceeded on yellow corn (Zea mays L.) in plastic pots during the agricultural season on August 4, 2021, which included adding organic matter (0% and 5%) and bentonite mineral (0%, 10%, and 20%) of soil weight and potassium (0, 50, and 100 kg ha^-1) as potassium sulfate. After 90 days of planting, the amount of soluble and exchangeable potassium measured revealed results that adding organic matter with bentonite minerals increased soluble potassium by 38.46%. Meanwhile, exchangeable potassium decreased by 1.61% and dry matter increased by 6.5%. As for adding bentonite, the 20% level was the most effective compared with 0% and 10%, in reducing soluble potassium by 25% and 50%. It also increased exchangeable potassium by 1.62% and 2.45% and dry weight of the plant by 95.04% and 48.32%. As for the effect of the added potassium levels, the results showed 100 kg ha^-1 was superior to 50 and 0 kg ha^-1 in soluble potassium (92.86% and 440%, respectively). The drained potassium was the highest at the level of 100 and 50 kg ha^-1 (5.88% and 5.04%) in the direction of the contact line, and 100 kg ha^-1 was superior to 100 and 50 kg ha^-1 in the dry weight of the plant (9.85% and 4.80%). The results of the double and triple interaction showed significant differences.

Keywords: Yellow maize (Z. mays L.), organic matter, bentonite, potassium fertilizer, growth traits

Key findings: The addition of organic matter and bentonite to sandy soils can improve potassium availability and reduce the values of exchangeable potassium, aside from improving the yellow maize corn (Z. mays L.) growth.

The field experiment on maize (Zea mays L.) during the autumn of 2020 revealed the effects of irrigation periods and mulching on its growth and yield-related traits. The study, held at the Bad’at al-Musayyab region, Babylon province, Iraq, had the experiment laid out in a randomized complete block design (RCBD) with factorial arrangement, two factors, and three replications. The first factor was the irrigation intervals (4, 8, and 12 days), while the second comprised two mulching methods (straw mulching and no mulching). The irrigation intervals, mulching treatments, and their interactions revealed significant differences for most growth and yield-related traits in maize. The least irrigation interval (four days) excelled in achieving the highest mean values for plant height (195.00 cm), leaves per plant (16.31), leaf area (697.9 cm²), chlorophyll index (63.16 SPAD), ears per plant (1.88), grains per ear (602.5), and grain yield (12.55 t ha^-1), compared with the maize crop irrigated with a 12-day interval. The latter recorded the lowest means for the above-mentioned traits. The soil mulching treatment also excelled for the traits compared with non-mulching, which recorded the minimum values.

Keywords: Maize (Zea mays L.), irrigation intervals, soil mulching, interactions, growth and yield traits, physiological traits

Key findings: Maize (Zea mays L.) planting with straw mulching and irrigated every four days, promoted the growth and, eventually, boosted the yield components and grain yield of corn.

The research aimed to prepare a theoretical vision, including a set of proposed standards for developing work in Agricultural Extension Centers in the Central Governorates (Baghdad, Diyala, Babylon, Al-anbar, and Salah al-Din), within seven important guiding areas. Using the descriptive approach to conduct this study, the sample community included all agricultural extension workers working in research centers of central Iraq governorates, totaling 95 respondents. The two-part questionnaire served as a tool for collecting data from the respondents. The first part represented opinions of agricultural extension agents about the extent of application and adoption of suggested standards in the work of agricultural extension centers. Meanwhile, the second part included the respondents’ opinions about the degree of their approval of the proposal to develop the extension centers. The study concluded a large proportion of the respondents believe a weakness existed in the level of application of the recommended standards in the operation of the agricultural extension centers. It is evident in not adopting the principle of decentralization when formulating the goals of the extension centers.

Keywords: Agricultural Extension Centers, Central Governorates of Iraq, theoretical vision, research community, extension agents, decentralization

Key findings: A significant weakness in the coordination process and cooperation with relevant authorities exist. Similarly, a limitation occurs in the integration of many parties with common goals, with the objectives of extension programs not based on real data, surveys, and studies. It was evident most of the sample members agreed with the standards proposed by the policy and objectives of the counseling centers.

The study intended to find out the main cause of cowpea damping-off and root rot disease. Separating a group of fungi comprised Fusarium solani, Rhizoctonia solani, and Macrophomina phaseolina. Findings of the field survey revealed fungus F. solani appeared in all isolated samples. The testing of pathogenicity of all isolated fungal isolates led to choosing the F. solani (Fs2) isolate as the most pathogenic in the experiment’s implementation. The biological resistance of Bacillus subtilis and fungus Trichoderma harzianum bore testing, with their high efficiency observed in inhibiting the pathogenic fungus isolate. Biological bacteria with the highest concentration of 10^-7 appeared with an inhibition rate of 82.20%. The results showed effectiveness of the chemical pesticide in all the concentrations and were highly successful. The wooden canopy showed the effectiveness of the biological resistance in inhibiting the pathogenic fungus. Results showed interaction of the fungus with bacteria reduced the rate and severity of infection to zero. A significant superiority of the biological resistance elements was notable in reducing severity of infection compared with pathogenic fungus alone. The field results confirmed the woody canopy for the efficiency of the biotic resistance elements in reducing the rate and severity of infection, raising the growth of cowpea plants.

Keywords: F. solani, T. harzianum, B. subtilis, cowpea damping-off

Key findings: This study aimed to reveal the effectiveness of biological and chemical resistance elements in inhibiting the pathogenic fungus F. solani, which causes the death of cowpea plants, as well as, improving the growth parameters of the plants.