F1 Hybrids Research Articles

F1 Hybrid Seed Can Enhance Cannabis Crop Uniformity and Yield

Cannabis (Cannabis sativa) growers seek greater crop uniformity and yield; however, use of vegetatively propagated plants has several drawbacks. There is increased interest in F1 hybrid seed, especially for flower production. Plant growth and performance of inbred lines of the cultivars Wife (WF) and Wilhelmina (WH), produced from one to four rounds of selfing (S1 to S4), and three F1 hybrid lines (WF S1 × WH S1, WF S2 × WH S2, and WF S3 × WH S3) were evaluated. As selfing increased from S1 to S4, within line plant variation did not change substantially for most measures for WF, but variation progressively decreased for plant height, total shoot length and plant dry weight for WH. S4 plants of WH were uniformly diminutive and likely exhibited inbreeding depression. F1 hybrids between WF and WH were larger than WH plants for all measures because WH is photoperiod insensitive (autoflowering) and dwarf. Compared with WF self-lines, F1 WF × WH hybrid lines exhibited greater uniformity, plant dry weight, flower dry weight, and percent cannabidiol and tetrahydrocannabinol. F1 WF × WH hybrid plants were able to achieve similar height and shoot growth to WF self-lines, even though they had a dwarf parent in WH. It is likely that heterosis is responsible for the growth enhancements observed in the F1 WF × WH hybrids. These findings indicate that F1 hybridization can produce uniform, stable, and high-yielding cannabis plants from seed.

Genetic analysis on composition of sulfur-containing amino acids: methionine and cysteine in subtropical maize

Maize grains are deficient in sulfur-containing amino acids such as methionine (Met) and cysteine (Cys). To date, no maize hybrid rich in Met and Cys has been commercialized particulalry in the subtropical regions. In this study, molecular characterization among seven inbreds using 89 SSRs grouped them into three clusters. The average genetic dissimilarity (GD) coefficient and gene diversity among these inbreds were 0.708 and 0.478, respectively. These seven inbreds were crossed in 7 × 7 half-diallel mating design, and the resulting 21 F1 hybrids along with four popular hybrid checks were evaluated across three locations viz., Delhi, Vagarai and Gauria Karma. Genetic analysis revealed that additive gene action predominantly controls Met content of f, while, both additive and non-additive gene action are important for Cys. Met and Cys levels varied from 0.058-0.306% and 0.025-0.126% with mean of 0.196% and 0.060%, respectively. Promising hybrids identified include MGU-MH-20 (Met: 0.306%, Cys: 0.040%, grain yield: 8136kgha-1), MGU-MH-17 (Met: 0.269% Cys: 0.045%, grain yield: 8178kgha-1), MGU-MH-19 (Met: 0.254%, Cys: 0.048%, grain yield: 8588kgha-1), and MGU-MH-18 (Met: 0.253%, Cys: 0.034%, grain yield: 9812kgha-1) were identified. No correlation was observed among Met, Cys, grain yield and GD. This study is the first to examine the genetics of Met and Cys accumulation in maize. Our findings provide valuable insights for the development of high Met and Cys maize cultivars, which are vital to mitigate malnutrition, especially in developing countries.

Identification of Best General and Specific Combiners for Soybean Improvement

The present study on general combining ability effects and specific combining ability effects involves 15 parents viz., lines RKS 18, RKS 113, AUKS 199, AUKS 200, AUKS 212, RVSM 2011-35, JS 20-98, AUKS 202, AUKS 208, AUKS 218, JS 21-72, NRC 165 and tester JS 20-34, NRC 138, SL 958 with their 36 F1 hybrid through Line x Tester mating system. The present investigation was undertaken using Randomized Block Design with three replications. The combining ability effects were estimated for thirteen characters viz., days to 50% flowering, days to maturity, plant height, number of branches per plant, number of pods per plant, pod length, number of seeds per pod, 100-Seed weight, seed yield per plant, biological yield per plant, harvest index, protein content and oil content. The result showed that gca effects of parents and sca effects of hybrids were significant differed. Among the parents, AUKS 212 was found to be good general combiner based on the per se performance and gca effects for seed yield and other contributing traits and four hybrids AUKS 113 x SL 958, RVSM 2011-35 x NRC 138, AUKS 199 x JS 20-34 and NRC 165 x JS 20-34 were superior high sca effects for seed yield and yield contributing traits. These crosses can be utilized in future breeding programmes and exploitation of better segregants through pedigree method or single seed descent method in advance generations for improvement of yield and yield attributes coupled with quality traits sound soybean genotypes.

Evaluation of F1 hybrids against root knot nematode (<i>Meloidogyne incognita</i>) resistance in Brinjal (<i>Solanum melongena</i> L.)

Brinjal is one of the most important commercial solanaceous vegetable crops. Root knot nematodes cause severe yield losses in brinjal both in open and poly house conditions. Host plant resistance is considered to be a viable solution and cost-effective method to manage the root knot nematodes. Ten genotypes along with their nineteen F1 hybrids were screened for resistance to root knot nematode and biochemical basis of resistance was assessed. Two F1 hybrids viz., IIHR-824 x VI046101, IIHR-824 x IIHR-766, parents viz., IIHR-824 and VI046103 were found to be resistance to M. incognita with gall index/ egg mass index of 1. Three F1 hybrids, IIHR-824 x IIHR-356, IIHR-824 x IIHR-835, VI046103 x IIHR-834 showed moderately resistant reaction. The root biochemical compounds analysis indicated that, total phenolic content (67.05 mg/g) and flavonoids (121.32 mg/g) were found higher in the inoculated roots of resistant line i.e. IIHR-824 indicating their role in conferring resistance. The identified F1 hybrids having resistance can be explored for commercial cultivation.

Cas9/guide RNA-based gene-drive dynamics following introduction and introgression into diverse anopheline mosquito genetic backgrounds.

Novel technologies are needed to combat anopheline vectors of malaria parasites as the reductions in worldwide disease incidence has stalled in recent years. Gene drive-based approaches utilizing Cas9/guide RNA (gRNA) systems are being developed to suppress anopheline populations or modify them by increasing their refractoriness to the parasites. These systems rely on the successful cleavage of a chromosomal DNA target site followed by homology-directed repair (HDR) in germline cells to bias inheritance of the drive system. An optimal drive system should be highly efficient for HDR-mediated gene conversion with minimal error rates. A gene-drive system, AgNosCd-1, with these attributes has been developed in the Anopheles gambiae G3 strain and serves as a framework for further development of population modification strains. To validate AgNosCd-1 as a versatile platform, it must perform well in a variety of genetic backgrounds. We introduced or introgressed AgNosCd-1 into different genetic backgrounds, three in geographically-diverse Anopheles gambiae strains, and one each in an An. coluzzii and An. arabiensis strain. The overall drive inheritance, determined by presence of a dominant marker gene in the F2 hybrids, far exceeded Mendelian inheritance ratios in all genetic backgrounds that produced viable progeny. Haldane's rule was confirmed for AgNosCd-1 introgression into the An. arabiensis Dongola strain and sterility of the F1 hybrid males prevented production of F2 hybrid offspring. Back-crosses of F1 hybrid females were not performed to keep the experimental design consistent across all the genetic backgrounds and to avoid maternally-generated mutant alleles that might confound the drive dynamics. DNA sequencing of the target site in F1 and F2 mosquitoes with exceptional phenotypes revealed drive system-generated mutations resulting from non-homologous end joining events (NHEJ), which formed at rates similar to AgNosCd-1 in the G3 genetic background and were generated via the same maternal-effect mechanism. These findings support the conclusion that the AgNosCd-1 drive system is robust and has high drive inheritance and gene conversion efficiency accompanied by low NHEJ mutation rates in diverse An. gambiae s.l. laboratory strains.

Mutations in CsWOX4 Regulate Leaf Vein Pattern and Leaf Size in Cucumber (Cucumis sativus L.)

The leaf morphology is an important agronomic trait in crop production. Our study identified a maple leaf type (mlt) cucumber mutant and located the regulatory gene for leaf shape changes through BSA results. Hybrid F1 and F2 populations were generated by F1 self-crossing, and the candidate mlt genes were identified within the 2.8 Mb region of chromosome 2 using map cloning. Through the sequencing and expression analysis of genes within the bulk segregant analysis (BSA) region, we identified the target gene for leaf shape regulation as CsWOX4 (CsaV3_2G026510). The change from base C to T in the original sequence led to frameshift mutations and the premature termination of translation, resulting in shortened encoded proteins and conserved WUSCHEL (WUS) box sequence loss. The specific expression analysis of the CsWOX4/Cswox4 genes in the roots, stems, leaves and other tissue types of wild-type (WT) and mutant plants revealed that CsWOX4 was higher in the root, but Cswox4 (mutant gene) was significantly higher in the leaf. Subcellular localization analysis revealed that CsWOX4 was localized in the nucleus. RNA-seq analysis revealed that the differentially expressed genes were mainly enriched in the mitochondrial cell cycle phase transition, nucleosome and microtubule binding pathways. Simultaneously, the quantitative analysis of the expression trends of 25 typical genes regulating the leaf types revealed the significant upregulation of CsPIN3. In our study, we found that the conserved domain of CsWOX4 was missing in the mutant, and the transcriptome data revealed that the expression of some genes, such as CsPIN3, changed simultaneously, thereby jointly regulating changes in the cucumber leaf type.

Genetic Variability Studies in Chickpea (Cicer arietinum L.) for Yield and Contributing Traits Through Half-diallel Mating Strategy under Late-sown Conditions

Background: One of the oldest cultivated legumes, chickpeas (Cicer arietinum L.), are essential for world nutrition, especially with climate change. Chickpea output is poor despite rising demand for its nutritional value. Improved genetics can enhance yields to fulfil local and global demands. By selecting better parents and potential hybrids utilising half-diallel mating, breeders can hasten the development of high-yielding, durable cultivars. Methods: This study examined 55 half-diallel mating genotypes, comprising 10 parental lines and 45 F1 hybrids. At the Acharya Narendra Deva University of Agriculture and Technology Genetics and Plant Breeding Farm in Ayodhya, U.P., these were evaluated using a randomised block design with three replications under late-sown circumstances in 2022-23 rabi. Normal agricultural procedures were used. A four-meter row of each genotype was planted with 30 cm between rows and 10 cm between plants. Genetic indices like GCV, PCV, heritability, genetic progress, correlation coefficient and path analysis were evaluated. Result: ANOVA revealed significant genetic variability across all traits. Biological yield plant-1 had the highest PCV and GCV, followed by seed yield plant-1. Heritability and genetic progress were highest for days to 50% flowering and biological yield plant-1, indicating strong genetic control. Days to 50% flowering and maturity inversely linked with most yield-related characteristics. Seed yield was closely associated with primary and secondary branches plant-1, plant height, pods per plant, seeds pod-1, 100-seed weight and biological yield. Path coefficient study showed that all characteristics except days to 50% flowering, days to maturity and plant height influenced grain yield.

The ZmCPK39-ZmDi19-ZmPR10 immune module regulates quantitative resistance to multiple foliar diseases in maize.

Gray leaf spot, northern leaf blight and southern leaf blight are three of the most destructive foliar diseases affecting maize (Zea mays L.). Here we identified a gene, ZmCPK39, that encodes a calcium-dependent protein kinase and negatively regulates quantitative resistance to these three diseases. The ZmCPK39 allele in the resistant line displayed significantly lower pathogen-induced gene expression than that in the susceptible line. A marked decrease in ZmCPK39 abundance mitigated the phosphorylation and degradation of the transcription factor ZmDi19. This led to elevated expression of ZmPR10, a gene known to encode an antimicrobial protein, thereby enhancing maize resistance to foliar diseases. Moreover, the F1 hybrid with reduced ZmCPK39 expression favored disease resistance, thereby increasing yield. Hence, the discovery of the ZmCPK39-ZmDi19-ZmPR10 immune module provides insight into the mechanisms underlying broad-spectrum quantitative disease resistance and also offers a new avenue for the genetic control of maize foliar diseases.

Effect of Black Soldier Fly Larvae Frass as Organic Fertilizer on Postharvest Quality and Shelf Life of Open-field-grown Tomato (Solanum lycopersicon L.)

Open-field-grown tomatoes in Saudi Arabia are stressed by poor soil fertility because of the low organic matter content, low nutrient availability, and high pH. Thus, high chemical fertilizer inputs are crucial for commercial production; however, they cause economic loss as well as negatively affect environmental sustainability. The use of efficient organic fertilizers would be useful for developing more cost-effective, environmentally friendly, and sustainable agriculture. The current study evaluated the impact of Black soldier fly (Hermetia illucens L.) frass (BSFF) fertilizer applications as organic fertilizer on postharvest fruit quality and shelf life of open-field-grown F1 hybrid ‘Sinag Tala’ tomatoes compared with those grown under control treatment (received recommended doses of chemical fertilizers for tomato production under open field conditions). The experiment was conducted using a randomized complete block design with four replicates. The results showed that the application of BSFF fertilizer, especially at the higher rate (5 ton/ha; BSFF3), improved the overall quality of tomato fruit. The BSFF fertilizer treatments reduced weight loss, maintained higher firmness, antioxidants [vitamin C, total phenol content (TPC) and total flavinoid (TFC)], total soluble solids (TSS), and titratable acidity (TA) contents, and lowered the TSS/TA ratio of fruits during shelf life compared with those of the control. The decay incidence was only detected after 9 days of shelf life and was significantly lower in all the BSFF fertilizer treatments (range, 8.40%-12.05%) than in the control (15.9%). In addition, BSFF fertilizer treatments reduced both disease incidence and severity of gray mold following pathogen inoculation during shelf life compared with those of the control. These results might be attributable to the higher antioxidants content (vitamin C, TPC, and TFC) and higher polyphenol oxidase activity in BSFF-fertilized tomatoes. In conclusion, BSFF fertilizer could be used as a potential eco-friendly alternative to chemical fertilizers to improve tomato fruit quality during shelf life.

Genome-wide analysis of detoxification genes conferring diamide insecticide resistance in Spodoptera exigua identifies CYP9A40

For over a decade, diamide insecticides have been effective against lepidopteran pests like beet armyworm, Spodoptera exigua (Hübner, 1808). However, the evolution of resistance poses a challenge to their sustainable use. We identified an I4790M mutation in the S. exigua ryanodine receptor (RyR) gene, but its correlation with resistance varied across the field-collected Korean populations of S. exigua. RNA sequencing and differential gene expression analysis were performed to investigate other resistance mechanisms. Diamide-resistant and susceptible strains and F1 hybrids were compared by mapping RNA-seq reads to the S. exigua reference genome. CYP9A40 was identified as a critical gene in diamide resistance due to its high expression in the resistant strains. Synergist bioassays with piperonyl butoxide supported the role of P450s in diamide metabolic resistance in S. exigua. A strong positive correlation between CYP9A40 over-expression levels (up to 80-fold) and diamide LC50 values was obtained for field-collected populations uniformly showing a 100% frequency of the RyR I4790M target-site resistance allele. To validate the function of CYP9A40 in diamide detoxification, we recombinantly expressed the gene and tested its ability to bind and degrade chlorantraniliprole as a substrate. The results confirmed its catalytic role in diamide metabolism. CYP9A40 has been identified and validated to confer metabolic resistance in Korean S. exigua populations. It works alongside the RyR target-site I4790M mutation to enhance diamide resistance. These mechanisms offer insights for resistance monitoring and support insecticide resistance management programs to improve control strategies for S. exigua.

Intersectional Hybrids of the Relict Species, Box Huckleberry (Gaylussacia brachycera), with Dwarf Huckleberry (Gaylussacia dumosa)

Gaylussacia brachycera (box huckleberry) is a unique relict species and is the monospecific member of Gaylussacia sect. Vitis-idaea. As part of investigations to understand interspecific crossability in Gaylussacia, pollinations were made between evergreen 2x G. brachycera and deciduous 2x G. dumosa (dwarf huckleberry). The primary pollinations succeeded at a low level and produced four viable hybrids. Three of these hybrids had box huckleberry as the female, and one of them, dwarf huckleberry, as the female. Morphologically, these hybrids were distinct from the parents and were generally intermediate. The fertility of the hybrids was low, but one hybrid flowered sufficiently to allow collection of pollen and to backcross it as a male to box huckleberry. Four BC1 hybrids were produced from this cross. The F1 and BC1 hybrids were all verified using simple sequence repeat markers developed for the closely related genus Vaccinium. These hybrids are notable for being the first recorded hybrids of this rare species, G. brachycera, with any other Gaylussacia species, and these hybrids are expected to lead to a better understanding of species relationships both within Gaylussacia and between Gaylussacia and Vaccinium.

Research of Carthamus tinctorius L. F1 hybrids in the conditions of the Northern Caspian region

Research of Carthamus tinctorius L. F1 hybrids in the conditions of the Northern Caspian region

Effect of the addition of IGF-1 during in vitro culture on the embryonic development speed from different crossbreed bovine embryos.

Supplementation with insulin-like growth factor type 1 (IGF-1) during in vitro culture of bovine embryos has yielded mixed results, likely due to genetic variability among embryos. This work aimed to evaluate the effect of IGF-1 at two concentrations on the development speed embryos from primary F1 crossbreeds used in dual-purpose cattle farming in the Colombian low tropics. Specifically, we investigated the influence of IGF-1 and embryo breed on the blastocyst formation rate. Oocytes were sourced from non-pregnant cows: Bos taurus indicus (20 Brahman and 14 Gyr) and Bos taurus taurus (12 Holstein and 28 Romosinuano). Oocytes were fertilized with semen from specific bulls (Recoil for Holstein, Gabinete for Gyr, and UBER POI 1490 for Brahman). The resulting embryos from each crossbreed group were randomly distributed in three different cultured media with 50 ng/mL IGF-1, 100 ng/mL IGF-1, or no IGF-1 (control) for 7 days. Results showed that 50 ng/mL IGF-1 significantly increased embryo production by day 6 (25.9%±14.56%) compared to control (20.5%±11.84%) and 100 ng/mL IGF-1 (23.0%±9.54%) (p < 0.05). By day 7, both 50 ng/mL (42.6%±26.55%) and 100 ng/mL (49.7%±21.98%) IGF-1 groups exhibited significantly higher production rates compared to the control group (p < 0.001). The embryo breed also influenced development, with Gyr-Holstein (GxH) crossbreeds showing the highest production rates (p < 0.001). In conclusion, IGF-1 supplementation enhances in vitro embryo production, with the effect influenced by both breed and IGF-1 concentration. These findings suggest that breed-specific optimization of IGF-1 conditions is necessary to maximize embryonic development outcomes.

Absence of heterosis for hypoxia tolerance in F1 hybrids of Tigriopus californicus.

Hybridization produces a range of outcomes from advantageous to disadvantageous, and a goal of genetic research is to understand the gene interactions that generate these outcomes. Interactions between cytoplasmic elements, such as mitochondria, and the nucleus may be particularly vulnerable to accruing disadvantageous combinations as a result of their different rates of evolution. However, mitonuclear incompatibilities often do not have an observable effect until the F2 and later generations. We used Tigriopus californicus, a model system for mitonuclear incompatibilities that is also known for exhibiting heterosis in the F1 generation, to test whether hypoxia was more stressful for mitonuclear interactions than other environmental stressors. We generated 284 parental and 436 F1 hybrids from four population crosses (720 total) and compared parental and F1 populations for hypoxia tolerance. We observed that, on average, F1 hybrids were less likely to survive a hypoxia stress test than parental populations (Parental:F1 coefficients ranged from -0.04 to 0.14 with none significantly different from 0). This suggests that hypoxia may be a particularly intense stressor for mitonuclear coordination, and that hybridization outcomes vary by trait.

Contrast and Genomic Characterisation of Ancient and Recent Interspecific Introgression Between Deeply Diverged Moustache Toads (Leptobrachium).

Recent genomic analyses have provided new insights into the process of interspecific introgression and its consequences on species evolution. Most recent studies, however, focused on hybridization between recently radiated species, with few examining the genomic outcomes of ancient hybridization across deeply diverged species. Using whole genome data of moustache toads (Leptobrachium), we identified signals of three hybridization events among nine species that diverged at the Eocene. An ancient introgression from L. leishanense to the ancestral branch (C1) of L. liui introduced adaptive variants. The highly introgressed regions include genes with important functions in odorant detection and immune responses. These genes are preserved in all three descendent populations of L. liui_C1, and these regions likely have been positively selected over a long filtering process. A recent introgression occurred from L. huashen to L. tengchongense, with the introgressed regions being mostly neutral. Furthermore, one F1 hybrid individual was detected between sympatric L. ailaonicum and L. promustache. The signals of introgression largely disappeared after removing the hybrid individual, indicating an occasional hybridization but minimal introgression. Further examination of highly divergent but low introgressed genomic regions revealed both pre-mating isolation and genetic incompatibility as potential mechanisms of resisting introgression and maintaining species boundaries. Additionally, no large X-effect was found in these introgression events. Hybridization between deeply diverged amphibian species may be common, but detectable introgressions are likely less so, with recent introgression being mostly neutral and the rare ancient one potentially adaptive. Our findings complement recent genomic work, and together they provide a better understanding of the genomic characteristics of interspecific introgression and its significance in species adaptation and evolution.

Active avoidance learning in rats with different audiogenic epilepsy proneness

The success of the formation of the conditioned reflex reaction of two-way avoidance in the shuttle chamber in rats of 3 strains was evaluated. These were rats predisposed to audiogenic epilepsy – the Krushinsky-Molodkina strain rats (KM), "4" strain (selected from a population of F2 hybrids of the KM strain and sound-insensitive Wistars) and rats of "0" strain, selected for the absence of audiogenic epilepsy from the same population (i. e. these strains, diametrically different in audiogenic epilepsy proneness, possessing a similar genetic background). Experiments have shown significantly more successful assimilation of this skill in rats of the "0" strain.

Assessment of Lethal, Sublethal, Transgenerational, and Biochemical Effects of Isaria fumosorosea on Mythimna separata.

Mythimna separata is a destructive polyphagous pest of field crops. Insecticides are generally applied for its control which not only negatively affect natural enemies and the environment and cause resistance in the insect pests. There is a need for the friendly method which is safe for the environment and life. Currently, entomopathogenic fungi are being used as biological control agents for different insects. The influence of Isaria fumosorosea on survival, life table parameters, and enzymatic activities of M. separata were assessed. On the seventh day post-treatment, the highest concentration 3 × 108 spores/mL-1 caused the 92.5% larval mortality. The effect of LC15 and LC50 of I. fumosorosea were recorded on parental generation (F0) and first filial generation (F1) of M. separata. The life table parameters of F1 showed a decreasing trend in the intrinsic rate (r), net reproductive rate (Ro), mean generational time (T), total larval duration, and fecundity ratio in treated groups. In LC15 and LC50, groups the average fecundity ratio was 319.2 and 191.18 eggs/female, respectively. The activities of detoxifying enzymes were concentration-dependent and highest activities were recorded on the third day. I. fumosorosea negatively affected the growth parameters of M. separata and can be included in M. separata management program.

The inheritance pattern for the dwarf phenotype in hybrids from crosses among sunflower lines differing in alleles of the Rht1 locus

Background. Sunflower seed production is based on utilization of the heterosis effect, manifesting itself in improving both yield and plant height in hybrids. Short-stemmed lines need to be used to develop commercial hybrids with an optimum height. Molecular bases of the trait manifestation in the dwarf lines from VIR’s sunflower genetic collection have not yet been studied. Materials and methods. The material included 27 short-stemmed and 10 tall sunflower lines from VIR’s genetic collection, as well as the F1 and F2 hybrid generations derived from crossing the tall (VIR 340) and dwarf (VIR 171) genotypes. The parental lines and hybrids were phenotyped for plant height, leaf number, and internode length. Genotyping for the Rht1 locus (HaDella1 candidate gene), encoding the negative regulator of the gibberellin response, the DELLA protein, was performed using the developed CAPS marker. Results. The average plant height in the VIR 340 line over a three-year study was 162 cm, the number of leaves 29, and the internode length 6 cm. The VIR 171 line demonstrated the plant height of 66 cm, leaf number of 24, and internode length of 2.8 cm. The F1 hybrids were uniform, with the height of 180–190 cm, that indicated the dominance of the long stem trait. Analyzing the segregation in the F2 hybrid generation led to an assumption admitting the digenic control of the dwarf phenotype in the VIR 171 line. The CAPS marker G-D-1/ Bmt I was developed to identify a missense mutation T&gt;C in the first exon of the HaDella1 gene, which results in the substitution of leucine with proline in the DELLA motif. Using the marker, the mutant Rht1 allele was identified in the VIR 171 and VIR 434 dwarf lines, similar in their origin and phenotype. The results of validation in the F2 hybrid population (VIR 340 × VIR 171) confirmed the efficiency of the G-D-1 / Bmt I marker for selecting dwarf genotypes homozygous for the Rht1 mutant allele.

Mean Performance and Heterotic Pattern of Maize (Zea mays L.) Inbred Lines Adapted to Sub-humid Central Highland of Ethiopia

In spite of abiotic and biotic stresses and low availability of high-yielding cultivars restrict potential production of maize, it is a major food crop in Africa. To overcome this production barrier, promising germplasm must be chosen, combining ability must be understood, and heterotic groups must be formed in order to generate high-yielding maize varieties. The study set out to evaluate plant height, ear height, ear diameter, thousand seed weight, kernel per row, kernel row per ear, and number of ear per plant in order to assess the performance evaluation and heterotic pattern of inbred lines. In 2019, twenty-six inbred lines and two single cross testers were crossed using a line by tester mating design to create fifty-two three way cross F1 hybrids. The experiment, which used an alpha lattice design with two replications, was conducted at the Ambo and Kulumsa Agricultural Research Centers during the 2020 cropping season. Analyses of variance revealed that among the parameters with significant mean squares arising from crosses and lines both within and across locations were grain yield, anthesis date, silking date, plant height, ear height, kernel row per ear, and number of ears per plant. Because of the lines, testers, and crossings for grain yield, anthesis date, silking date, plant height, ear height, kernel row per ear, and number of ear per plant, the line x tester ANOVA results revealed significant mean squares. Due to line x site, line x tester, tester x site, and line x tester x site, there was a noticeable difference in plant height, ear height, and the number of ears per plant. This proved that different environment have different selection criteria for materials and different performance levels. This genetic study Categorized, L1, L22, and L24 under heterotic group A (CEL08008/CEL08047), while L8, L10, L14, L17, L20, and L26 were placed under heterotic group-B (CEL08024/CML561).

Assessment of Combining Ability for Yield and Associated Traits in Sunflower (Helianthus annuus L.)

The study was carried out at the Oilseeds Research Station, Latur. During kharif 2023, crosses were produced and during Rabi 2023–24, evaluation was conducted to assess the combining ability for seed yield and component traits in parents and hybrids in sunflower. In this study, 48 F1 hybrids were produced through Line x Tester mating design during Kharif 2023 using six CMS lines (DSF-2 A, CMS 148A, CMS 47A, CMS 597A, CMS 103A, CMS 112A) and eight testers (RHA-1055, EC-601951-1, EC-601924, R-274, LTRR-341, AKSF-15R, BK-R-1, R-856). These hybrids were assessed using a Randomized Block Design with two replications at the Oilseeds Research Station in Latur during Rabi 2023–24, together with their 14 parent lines and two commercial checks (LSFH-171 and KBSH-44). The observations were recorded on five randomly selected plants and the average value of these data was calculated for ten quantitative attributes. The analysis of combining ability (GCA and SCA) effect was came out by using the Line x Tester analysis method suggested by Kempthorne [1]. The significance of GCA and SCA effects was determined at the 0.05 and 0.01 level using the t-test [2]. All characteristics had substantial significant variance due to line x tester effects. The existence of non-additive gene action for days to maturity, head diameter, seed filling, 100 seed weight and seed yield per plant were recorded. The per cent contribution of testers towards total variance was greater than lines for all the characters except plant height. Among the parents, two lines CMS-597 A and CMS-47 A and four testers RHA-1055, EC-601924, R-274 and AKSF-15R were found to be superior general combiners for seed yield per plant and most of the yield contributing traits. On the basis of mean performance, SCA effects of crosses and GCA effects of the parents, the crosses viz., CMS-112 A x AKSF-15R, CMS-148 A x RHA-1055, CMS-597 A x R-856, CMS-47 A x R-274, CMS-597 A x LTRR-341, CMS-112 A x EC-601924 and CMS-597 A x EC-601951-1 recorded high SCA effect with low x high, low x high and high x high GCA status of parents for seed yield per plant.