Production Of F1 Hybrids Research Articles

Создание во ВНИИМК несуществующей в природе озимой формы горчицы сарептской (обзор)

Breeding of a new winter form of mustard started at the V.S. Pustovoit All-Russian Research Institute of Oil Crops in 1959. This work was aimed on increasing of crop yield due to winter plant growth. Hybrids between winter rapeseed and spring mustard were used as initial material. These species cross easily and had fertile progenies. A breeding sample No. 7823 was selected in hybrid combinations; it withstands low temperatures – from minus 10 to minus 15 °C at autumn sowing. At favorable overwintering conditions, yield of this sample was 2.0–2.8 t/ha, oil content of seeds – 44–48%. During further works, the winter mustard samples No. 26205 and 25582 with yield of 3.65–4.06 t/ha were selected. However, in unfavora-ble winter conditions, the winter resistance of winter mustard was 30–40% low than of winter rapeseed. In 1968, another method to develop winter mustard was chosen: by resynthesis from the elementary species – winter turnip rape (genome AA) and black mustard (genome BB). Usage of grafting and gamma radia-tion of pollen allowed producing F1 hybrid seeds. As a result of long-term works (1971–1989), based on resynthesis hybrids, the first in the world practice variety of winter mustard Suzdalskaya was developed. It competed with winter rapeseed by seed yield and winter resistance, however, erucic acid content in seed oil was 35–37%. In 2002, the first erucic acid free (1.5%) variety of winter mustard Snezhinka was submitted for the State trial. In 2010, the absolutely erucic acid free variety of winter mustard Dzhuna was included into the State register of breeding achievements. In 2022, the variety Vyuzhanka was included into the State Register, it exceeds the variety Dzhuna by seed yield by 0.72 t/ha and has oil of high quality.

F1 Hybrids in oil palm

F1 Hybrid production in oil palm (Elaeis guineensis) is a reality. F1 Hybrids have the potential to provide massive increases in yield as demonstrated in a range of crops. Verdant has the intellectual property and “know-how” to produce haploids and double them to give doubled haploids. Doubled haploids are fertile and 100% homozygous (genetically pure lines), making them ideal as parents for F1 Hybrids. There has been no genetic modification. Verdant now has a collection of Dura and Pisifera doubled haploids that span the genetic diversity of oil palm from which parents can be selected based on genetic contrasts (using Diversity Array Technology). The first F1 Hybrid crosses (Dura x Pisifera) were made in 2019 and field progeny trial testing started in 2021. Performance in the field is being monitored by a range of physiological tests, but ultimately on palm product yield per hectare plus commercially significant secondary traits, such as disease tolerance, will determine selection. The intention is to start commercial F1 Hybrid seed production in 2029. A phenomics nursery has been set up to correlate seedling physiological traits with yield with the aim of developing early indicators for yield potential and to screen for variation between crosses for 1) Ganoderma tolerance, 2) nutrient uptake, and 3) drought tolerance. Genotyping is also being deployed to identify and select heterotic combinations that result in hybrid vigour.

Strong plastic responses in aerenchyma formation in F1 hybrids of Imperata cylindrica under different soil moisture conditions.

Hybrids can express traits plastically, enabling them to occupy environments that differ from parental environments. However, there is insufficient evidence demonstrating how phenotypic plasticity in specific traits mediates hybrid performance. Two parental ecotypes of Imperata cylindrica produce F1 hybrids. The E-type in wet habitats has larger internal aerenchyma than the C-type in dry habitats. This study evaluated relationships between habitat utilisation, aerenchyma plasticity, and growth of I. cylindrica accessions. We hypothesize that plasticity in expressing parental traits explains hybrid establishment in habitats with various soil moisture conditions. Aerenchyma formation was examined in the leaf midribs, rhizomes and roots of two parental ecotypes and their F1 hybrids in their natural habitats. In common garden experiments, we examined plastic aerenchyma formation in leaf midribs, rhizomes and roots of natural and artificial F1 hybrids and parental ecotypes and quantified vegetative growth performance. In the natural habitats where soil moisture content varied widely, the F1 hybrids showed larger variation in aerenchyma formation in rhizomes than their parental ecotypes. In the common garden experiments, F1 hybrids showed high plasticity of aerenchyma formation in rhizomes, and their growth was similar to that of C-type and E-type under drained and flooded conditions, respectively. The results demonstrate that F1 hybrids of I. cylindrica exhibit plasticity in aerenchyma development in response to varying local soil moisture content. This characteristic allows the hybrids to thrive in diverse soil moisture conditions.

Breeding of some cucumber hybrids according to some water stress criteria under plastic houses conditions

The study was conducted at the College of Agriculture - University of Anbar during three agricultural seasons, the autumn of 2021 and the spring and autumn of 2022, with the aim of producing F1 hybrids of cucumbers for greenhouses that are resistant to drought stress. Four Gynoecious lines were used, which were planted in the autumn season 2021, and 12 reciprocal and reverse hybrids were produced by full Diallel-crosses, and then planted in the spring season 2022 for the purpose of performance evaluation. Three hybrids were selected that were superior in characteristics of growth and yield with the best parents and a certified hybrid for comparison (Kanz) planted in the autumn season 2022 in an experiment carried out within the design of split plots with two factors according to the randomized complete block design (RCBD) and with three replications. The first factor included 6 genotypes and the second factor included two levels of moisture depletion at 25% and 50% of the available water calculated on the weight method, and the results were as follows. The results of evaluating the performance of the produced combinations showed the superiority of three hybrids, 4×1, 4×3, and 1×4, as they recorded distinct yields of 4.97, 4.38, and 4.20 kg plant-1 respectively. The same hybrids recorded a significant positive hybrid vigor of 34.84%, 18.91% and 14.03%, respectively. The same hybrids were introduced into the third season experiment with the two best parents, 4 and 1, and it appeared that the 4×1 hybrid excelled in plant yield, amounting to 4.06 kg plant-1, and recorded the best values in all studied stress tolerance criteria, as it reached 4.06 and 4.05 in MP and GMP criteria respectively, and in SSI, YR and TOL criteria, it recorded values of 0.70, 0.10 and 0.42, respectively, and in STI, HM, YI, and DI criteria, values of 1.22, 4.05, 1.22, and 0.94, respectively while the parent P1 recorded the lowest values in stress tolerance criteria. From study concluded that the differences in the chemical responses and the amount of production of cucumber, due to the genetic variation of the genotypes under study. Three locally produced hybrids achieved superiority in yield during high moisture depletion. We recommend preserving parents 1 and 4 due to their distinctiveness and using them to produce distinctive hybrids.

Production and Evaluation of F1 Hybrids of Protected Cultivation Cucumber

The study was conducted in the College of Agriculture, University of Anbar, in the Autumn season of 2021 and spring 2022, in an unheated greenhouse. Four pure lines of Gynoecious cucumbers for protected cultivation were used, and full diallel cross were conducted in all directions to produce 12 reciprocal and reverse hybrids of the F1. The seeds of the parents and the resulting hybrids were sown. Including it with an approved hybrid (Kanz) for the purpose of comparison, which numbered 17 genotypes according to the design of Randomized Complete Block Design (RCBD) with three replications to evaluate the parents and the resulting hybrids and estimate some genetic parameters and the type of genetic action. The results showed that there were significant differences in the studied lines, as parents P4 and P1 showed superior over the other of the parents, as father 4 gave the best results for the parents in the characteristics of the number of nodes on the plant, leaf area, number of fruits and plant yield, which amounted to 36.32 node plant−1, 114.74 dm2 plant−1, 55.35 fruit plant−1 and 4.59 kg plant−1, and parent 1 did not differ from parent 4 in most characteristics, while parent 2 recorded the lowest results in all characteristics. The average heritability in the broad sense of the reverse effect was greater than the reciprocal effect and the low degree of heritability in the narrow sense, which indicates the possibility of Hybridization to obtain the desired characteristics and to obtain distinct hybrids.

Floral morphology of 'Anand' rapid cycling Brassica oleracea .

Abstract The 'Anand' type of cytoplasmic male sterility (CMS) was introduced to Brassica oleracea through protoplast fusion (Cardi and Earle, 1997), providing a source of male sterility that is of value in producing F1 hybrid varieties of this species without the cold sensitivity of 'Ogura' cytoplasm. In this species, as in others in which it has been introduced, 'Anand' mitochondria are associated with flower abnormalities. The best lines have been used by commercial breeders. This paper describes 'Anand' flower abnormalities in further detail. Rapid cycling brassica with 'Anand' cytoplasm may have promise as a model system for research on floral patterning. Materials and Methods. Three lines of rapid cycling B. oleracea carrying the 'Anand' cytoplasm and one wild type were grown. The flower morphology of 'Anand' lines was classified as good in F25-F-1A, fair in F25-F-6B, and poor in F23-F-1B (Cardi and Earle, 1997). Seedlings were started in an indoor growth room, but were maintained in a naturally lit greenhouse at 20° night, 25° day during flowering. Five flowers on 5 plants of each line were examined. Results. Morphological abnormalities affected all floral parts (Table 1). There was substantial variation among flowers on individual plants and among lines but little within lines. Conclusions. "Good" flowers have large petals that push open the sepals before the carpel elongates. Female fertility could be reduced due to occlusion of the stigma or physical damage caused by the stigma pressing against the end of a sepal and kinking the style. Female fertility in some flowers was unlikely because the carpel suture failed to fuse. In some cases the edge of the split carpel was sepal-like, consistent with the absence of SEPALLATA expression. The stigma on a sepal represents the converse. Stamens were most strongly affected, with outer stamens most reduced. This whorl is the one most frequently suppressed in flowering plants (Masters, 1869). The number of stamens was reduced to varying degrees. First to be lost was one or both of the pair outside the petals. Then the outer pair inside the petals was affected. One or both of these stamens could either be lost or doubled to give 3 to 5 stamens. Again a positional cue for stamens appears to be weakened. Anther development was often limited, the expected and desired consequence of the Anand genotype. Some undehisced " good " anthers contained pollen. There is variation even among the lines initially described as " good ". Further selection among these may help identify those that are most promising for further use in hybrid production.

Development of novel interspecific hybrid between cultivated and wild species of okra [Abelmoschus esculentus (L.)] Moench through embryo rescue

A reproducible embryo rescue technique has been developed for producing YVMV resistant okra in which embryos developed through hand pollination between a cultivated okra species Abelmoschus esculentus (Cv. Pusa Sawani) and wild species, A. moschatus subsps tuberosus (IC 470750) were excised at a very specific stage and germinated on agar solidified medium containing a basic salt mixture and carbohydrate. The choice of carbohydrate and the growth conditions employed were demonstrated to markedly affect the germination percentage and subsequent plantlet development. This technique has been proved successful for the production of F1 hybrid when compared to conventional methods of hand pollination followed by post-zygotic development on plant itself, which generally leads to embryo abortion in case of interspecific hybridization between two sexually cross-incompatible species of okra. The trueness of interspecific hybrid plant obtained through embryo rescue technique from a cross between cultivated and wild species (tertiary to primary gene pool) of okra was confirmed by morphological and molecular characterizations. The two parents and F1 hybrid developed were characterized morphologically using DUS parameters set for okra. The optimization of this technique will overcome pre and post-fertilization barriers coming across in the interspecific hybridization process and will pave the way further for gene introgression through distant hybridization in okra.

EVALUATING COMBINING ABILITIES AND HETEROTIC EFFECTS FOR ENHANCED COTTON YIELD

The present research was conducted to evaluate heterosis in diallel crosses, determining general and specific combining abilities for yield-related traits and identifying top-performing genotypes for future breeding programs. A field experiment was conducted using selected genotypes (CIM-599, CIM-602, Shahkar, and NS-181) to produce F1 hybrids through frequent pollinations in a diallel fashion. Twelve F1 hybrids and their four parental genotypes were cultivated in a randomized complete block design with two replications. Yield-related traits including plant height, branches per plant, bolls per plant, lint percentage, boll weight, seed cotton yield, seed index, and lint index were recorded. Analysis of variance and combining ability effects analysis were performed to assess the significance of the genotypes and their interactions. Significant variability among parental genotypes was observed for yield-related traits, indicating genetic variation in the breeding material. Combining ability analysis revealed the predominance of non-additive gene action. General combining ability (GCA) effects were significant for most traits, with CIM-599 exhibiting the highest GCA effects. Specific combining ability (SCA) and reciprocal combining ability (RCA) effects were significant for various traits and hybrid combinations, indicating their potential for trait improvement. Notably, the hybrid combination CIM-599 x Shahkar exhibited substantial mid-parent heterosis for seed cotton yield, boll weight, and lint percentage. This cross also displayed notable SCA effects, indicating its importance for hybrid breeding. These findings highlight the potential of hybrid breeding for trait enhancement. Future breeding programs could leverage the insights gained here to create improved cotton varieties with enhanced yield.

Current insights and advances into plant male sterility: new precision breeding technology based on genome editing applications.

Plant male sterility (MS) represents the inability of the plant to generate functional anthers, pollen, or male gametes. Developing MS lines represents one of the most important challenges in plant breeding programs, since the establishment of MS lines is a major goal in F1 hybrid production. For these reasons, MS lines have been developed in several species of economic interest, particularly in horticultural crops and ornamental plants. Over the years, MS has been accomplished through many different techniques ranging from approaches based on cross-mediated conventional breeding methods, to advanced devices based on knowledge of genetics and genomics to the most advanced molecular technologies based on genome editing (GE). GE methods, in particular gene knockout mediated by CRISPR/Cas-related tools, have resulted in flexible and successful strategic ideas used to alter the function of key genes, regulating numerous biological processes including MS. These precision breeding technologies are less time-consuming and can accelerate the creation of new genetic variability with the accumulation of favorable alleles, able to dramatically change the biological process and resulting in a potential efficiency of cultivar development bypassing sexual crosses. The main goal of this manuscript is to provide a general overview of insights and advances into plant male sterility, focusing the attention on the recent new breeding GE-based applications capable of inducing MS by targeting specific nuclear genic loci. A summary of the mechanisms underlying the recent CRISPR technology and relative success applications are described for the main crop and ornamental species. The future challenges and new potential applications of CRISPR/Cas systems in MS mutant production and other potential opportunities will be discussed, as generating CRISPR-edited DNA-free by transient transformation system and transgenerational gene editing for introducing desirable alleles and for precision breeding strategies.

MOLECULAR ASSESSMENT OF GENETIC DIVERGENCE AMONG MAIZE GENOTYPES

Research carried out in 2021 at the Jeser Al-Musayyab Company, Baghdad, Iraq, determined the molecular variations among 10 inbred lines of maize (Zea mays L.), for use in the future production of promising F1 hybrids. DNA sequencing random polymorphism technology using Inter Simple Sequence Repeats (ISSR) with five primers (UBC 834, UBC 835, UBC 856, UBC 866, and UBC 897) assessed the genetic variations among the 10 inbred lines of maize. All five primers produced 29 bands, averaging 5.8 strips each primer. The four primers, UBC 834, UBC 835, UBC 866, and UBC 897, had produced the same and highest number of proliferators with molecular weights ranging from 100 to 2000 bp. The primer UBC 856 showed the lowest number, with a molecular weight of 100–500 bp. The total number of polymorphs was 24, with a percentage of 82.4%, with the lowest (80%) polymorphs recorded in the primer UBC 856. The least discriminatory efficiency and ability values were 17.24% and 16.66%, respectively. Relying on binary data and genetic divergence using the UPGMA method to create a genetic kinship tree, the maize lines were separated into two groups, i.e., A, B, secondary, and sub-secondary groups. The highest genetic similarity (with the lowest genetic divergence) was estimated according to the Nei and Li coefficient of 0.23 between the two lines HS and S-10. The presented findings can provide further guidance and help analyze the genetic diversity among the maize populations.

Molecular profiling of some blast resistance genes and analysis of physiological variability in rice plants produced by anther culture and hybridization

For genetic improvement of rice plants against blast fungus disease caused by Magnaporthe oryzae, eight rice genotypes including four Egyptian and four foreign genotypes which represented a broad range of variation for blast resistance and other several traits were used in this study through line X tester mating design to produce F1 hybrids used as source of anther culture. Results of analysis of variance showed highly significant differences for all studied traits indicating overall genetic variations among parents and hybrids suggested that specific combining ability referred heavily to the expression of studied traits. Data of anther culture experiment for parents (8 parents) and hybrids (15 crosses) showed highly significant differences for all studied traits which illustrate genetic variations through the used materials. The highest callus induction percentage was found for CR7 (18.3%) and P6 (14.0%) while, the lowest callus induction percentage was found for CR5 (2.0%) and CR1 (4.0%). On the other hand, nine out of 15 hybrids recorded regeneration percentage more than the highest parental genotypes. Anther culture-derived plants and their parental genotypes were evaluated for blast disease resistance according to artificial infection with 10 blast races. The results showed that resistance percentage varied between 10% and 100%. While all anther culture-derived plants showed high level of resistance (100%) against all tested blast races. For enzyme activities for catalase, peroxidase and polyphenol oxidase in anther culture-drived plants and their parent, results showed that line TC9 derived from CR9 gave the highest value for catalase activity (301). Also, CR11 and P4 recorded the high level of peroxidase and polyphenol oxidase activities, respectively. Moreover, genetic diversity among anther culture-derived plants and their parental genotypes using five SSR primers related to Pi5(t), Pikh, Pi-b, Pi-1 and Pi-ta blast resistance genes showed heterozygous bands in all tested genotypes. The highest PIC value recorded for RM 247 and RM 206 markers which had PIC values of 0.778 and 0.761, respectively. Out of the used five SSR markers, RM 247 was the most informative marker with amplicon size ranged from 134 to 242 bp. These markers are therefore useful markers for studying polymorphism concerning blast resistance in rice and hence can be used in the marker-assisted selection for blast resistance. While development of resistant genotypes is the most effective way to control rice blast disease, anther culture technique used in this study helpful in production of resistant double haploid plants used in rice preeding programe in Egypt.

Production of double haploid watermelon via maternal haploid induction.

Production of double haploid watermelon via maternal haploid induction.

Development of KASP molecular markers related to the fertility restoration of cytoplasmic male sterility in pepper

Cytoplasmic male sterility (CMS) and Restorer-of-fertility (Rf) breeding systems can save the cost of the production of F1 hybrid seed in crops. However, the breeding of the restorer lines is not easy and the current molecular markers related to Rf gene is not very versatile because of diverse genes regulating the restoration. In this study, 11 SNPs in the previous Rf gene mapping region near the 3’ end of chromosome 6 of pepper were used to develop the competitive allele-specific PCR (KASP) molecular markers. The results showed that KS23 was proposed to relate to the Rf genes with the restoring genotype A/A and the maintaining genotype G/G. There were 91.6% in consistency for KS23 between the genotyping results in F2 individuals. In addition, the accuracy of KS23 achieved 100% among six restorer lines and 67.8% among 44 inbred lines in universalities, respectively. These results provided an efficient and labor saving KASP marker related to Rf, which will be beneficial for the breeding of restorer lines and accelerate the utility of CMS/Rf system in the production of F1 hybrid seed in pepper.

Allele-specific Expression Reveals Multiple Paths to Highland Adaptation in Maize.

Maize is a staple food of smallholder farmers living in highland regions up to 4,000 m above sea level worldwide. Mexican and South American highlands are two major highland maize growing regions, and population genetic data suggest the maize's adaptation to these regions occurred largely independently, providing a case study for convergent evolution. To better understand the mechanistic basis of highland adaptation, we crossed maize landraces from 108 highland and lowland sites of Mexico and South America with the inbred line B73 to produce F1 hybrids and grew them in both highland and lowland sites in Mexico. We identified thousands of genes with divergent expression between highland and lowland populations. Hundreds of these genes show patterns of convergent evolution between Mexico and South America. To dissect the genetic architecture of the divergent gene expression, we developed a novel allele-specific expression analysis pipeline to detect genes with divergent functional cis-regulatory variation between highland and lowland populations. We identified hundreds of genes with divergent cis-regulation between highland and lowland landrace alleles, with 20 in common between regions, further suggesting convergence in the genes underlying highland adaptation. Further analyses suggest multiple mechanisms contribute to this convergence in gene regulation. Although the vast majority of evolutionary changes associated with highland adaptation were region specific, our findings highlight an important role for convergence at the gene expression and gene regulation levels as well.

Persilangan Dialel Penuh pada Beberapa Genotipe Melon (Cucumis melo L.)

Melon productivity in Indonesia can be increased through the use of hybrid varieties. In order to obtain superior hybrids, information on general combining ability (GCA) and specific combining ability (SCA) is needed as a guide in selecting parents and combinations of superior crosses effectively and efficiently and to obtain the necessary information about the action of genes controlling plant traits. The aim of this study was to estimate the combining ability and gene action of melon crosses using full dialelic crosses. The research was conducted at the Greenhouse of Brawijaya University, Karangploso District, Malang Regency. The genetic material used was five melon parents {ACD211303 (1), ACD211254 (2), ACD221362 (3), ACD231380 (4), ACD231265 (5) which were planted and crossed in full dialelic to produce F1 hybrids. This research was conducted by planting 25 melon genotypes in a randomized block design, repeated three times. The results of the analysis of variance showed significant differences for several growth characters, namely leaf length (cm), leaf width (cm), stem diameter (mm), plant length (cm) and flowering age (DAP). The analysis of SCA variants on the characters of leaf length, stem diameter, plant length and flowering age was higher than that of the DGU variant which indicated that non-additive gene action dominated the inheritance of most of the characters. Combining ability analysis showed that the mean square of general combining ability (GCA) was significantly good for all characters. The combination of 1x3, 1x4, 1x5, 2x5 and 3x4 crosses is a superior cross combination and deserves further consideration as a candidate for hybrid varieties.

Hybrid Seeds in History and Historiography.

Accounts of twentieth-century agricultural industrialization in the United States and beyond often center the production and distribution of commercial F1 hybrid seed as a pivotal development. The commercialization of hybrid corn seed in the 1930s was initially heralded as a science-driven advance in agricultural productivity. However, since the 1970s “hybrid seed” has been linked to many perceived perils attendant on industrialized agriculture, from the undermining of farmers’ independence to the diminishment of crop genetic diversity to the consolidation of corporate control over the global food system. First grouped with the semidwarf varieties of the Green Revolution to emblematize capital- and chemical-intensive agriculture, hybrids are today often lumped together with genetically modified (GM) varieties for much the same reason. This essay revisits the scholarship that helped produce this understanding of hybrid seed. It explores how and why the singular history of hybrid corn inflected understandings of crop breeding and seed production in general, contributing to lasting confusion about the promises and pitfalls of distinct approaches to crop development and the nature of hybrid seed.

Phylogenetically Distant BABY BOOM Genes From Setaria italica Induce Parthenogenesis in Rice.

The combination of apomixis and hybrid production is hailed as the holy grail of agriculture for the ability of apomixis to fix heterosis of F1 hybrids in succeeding generations, thereby eliminating the need for repeated crosses to produce F1 hybrids. Apomixis, asexual reproduction through seed, achieves this feat by circumventing two processes that are fundamental to sexual reproduction (meiosis and fertilization) and replacing them with apomeiosis and parthenogenesis, resulting in seeds that are clonal to the maternal parent. Parthenogenesis, embryo development without fertilization, has been genetically engineered in rice, maize, and pearl millet using PsASGR-BABY BOOM-like (PsASGR-BBML) transgenes and in rice using the OsBABY BOOM1 (OsBBM1) cDNA sequence when expressed under the control of egg cell-specific promoters. A phylogenetic analysis revealed that BABY BOOM (BBM)/BBML genes from monocots cluster within three different clades. The BBM/BBML genes shown to induce parthenogenesis cluster within clade 1 (the ASGR-BBML clade) along with orthologs from other monocot species, such as Setaria italica. For this study, we tested the parthenogenetic potential of three BBM transgenes from S. italica, each a member of a different phylogenetic BBM clade. All transgenes were genomic constructs under the control of the AtDD45 egg cell-specific promoter. All SiBBM transgenes induced various levels of parthenogenetic embryo development, resulting in viable haploid T1 seedlings. Poor seed set and lower haploid seed production were characteristics of multiple transgenic lines. The results presented in this study illustrate that further functional characterization of BBMs in zygote/embryo development is warranted.

Evaluation of yields on new varieties of hybrid watermelon

Watermelon is a very important commodity in food security, especially horticultural products. Watermelon hybrid varieties are proven to be able to increase production and income for watermelon farmers. Watermelon breeding continues to produce superior varieties. Pure strains of watermelon as parents in the propagation or production of hybrid watermelon seeds, are necessary for crosses between parents to produce F1 hybrids. Evaluation and selectionare important stages in a plant breeding program. The purpose of this study was to obtain information on theproduction of hybrid watermelons from the research team of the Politeknik Negeri Lampung watermelon breeder.This study used a Randomized Block Design with nine treatments (varieties) repeated three times. The results of the observations were analyzed using the LSD test at the 5% level. The results showed that the varieties WM200701 and WM200702 had dark skin color and red flesh. Sweetness level data were significantly different by 9.3 °brix andl0.15 °brix when compared to control (8.9 °brix). Varieties WM 200703 and WM 200706 have bright green skin color with thin stripes with red and yellow flesh color. WM 200704 and WM 200705 have red flesh and dark green skin with thick striations. WM 200703 has the highest fruit weight of 4.63 kg per fruit. The six hybrid varieties tested have the potential to be submitted for registration of the F1 hybrid watermelon variety.

Combining ability and heterosis in Sorgum (Sorghum bicolor L.)

For the sustainable improvement of sorghum (Sorghum bicolor L.), local genotypes were conventionally crossed in East Java, Indonesia to determine a) the crossing success of different genotypes, b) germination percentage and seed setting traits, and c) the combining ability and heterotic effect of sorghum parental genotypes and their F1 diallel hybrids. Three sorghum genotypes (‘Lamongan-1’, ‘Tulungagung-2’, and ‘Jombang’) from the local germplasm were collected from various regions in East Java, Indonesia, and were crossed in a complete diallel design. The experiment was carried out in a randomized complete block design with four replications during 2018–2019 at the Agrotechnology Laboratory, Faculty of Agriculture, University of Muhammadiyah, Malang, Indonesia. Results showed that the parental genotypes and their F1 hybrids exhibited significant differences in seed weight and seed diameter and nonsignificant differences in germination percentage and seed setting. The parental genotype ‘Tulungagung-2’ and its hybrids ‘Jombang’ × ‘Tulungagung-2’, ‘Tulungagung-2’ × ‘Lamongan-1’, and ‘Jombang’ × ‘Tulungagung-2’ presented the highest germination percentages, seed setting, seed weights, and seed diameters. The genotype ‘Tulungagung-2’ had the highest general combining ability and was identified as a good general paternal and maternal parent for the production of promising F1 hybrids. The hybrid ‘Jombang’ × ‘Lamongan-1’ had the highest specific combining ability for all of the characters and was recognized as a promising F1 hybrid for improving sorghum yield. Cluster analysis divided all of the parental genotypes and their F1 hybrids into two large groups with a similarity of 13.13%.

Efficacy of hybrid seed production through natural pollinators employing male sterility: Case study of ridge gourd [Luffa acutangula (Roxb.) L.] CGMS system

Potential of natural pollinators and manually assisted pollination for producing F1 hybrid seeds of ridge gourd hybrid ‘KRH 1’ was evaluated under open field condition for two seasons by growing male sterile line (KAU-LA-MS-101) and monoecious male fertile line (LA-102) in alternate rows. Investigation was carried out at the Department of Vegetable Science, College of Agriculture, Vellanikkara, Thrissur, India. Species diversity of the pollinators, peak foraging time of the pollinators, number of floral visits by pollinating bees and number of bees visiting a flower during stigma receptivity were recorded. Nectary glands of male and female flowers of KAU-LA-MS-101 and LA 102 were measured. Seed yield and seed quality related traits were also recorded following standard protocol. Male sterile plants produce small male flowers with tiny nectary glands when compared to that of LA- 102, but female flowers of male sterile line have larger nectary glands. Stingless bee (Tetragonula sp.), was the pollinator observed in the field during anthesis time with peak activity after 5.30 pm. Number of fruits, number of seeds per fruit and average seed weight were significantly different between male sterile line and monoecious male fertile line LA-102. Pollination efficiency of bees found to be high when compared to manual hands in terms of quality of seeds produced from male sterile plants. However manual hands proved to be better for inducing more number of seeds per fruit. Total seed yield per plant depends on the total number of fruits developed and pollination by bees induces the development of more flowers to maturity, thereby ensuring competitive seed yield. Seed yield per plant exhibited significant positive correlation with seed length, shoot length, root length, fresh weight, vigour index I and germination velocity index. Present investigation revealed the potential of male sterile line developed in ridge gourd for hybrid seed production. Alternate planting of fertility restorer line with the MS line and allowing open pollination with the assistance of bees will reduce the labour charge involved in hybrid seed production and quality seed can be made available at a competitive rate.