Burgeoning human population dents, globally, the brimming buffer stock as well as gain in food grain production. However, an imminent global starvation was averted through precise scientific ...intervention and pragmatic policy changes in the 1960s and was eulogized as the “Green Revolution”. Miracle rice and wheat obtained through morphometric changes in the ideotype of these two crops yielded bumper harvest that nucleated in Asia and translated into Latin America. The altered agronomic traits in these two crops were the result of tinkering with the phyto-hormone “Gibberellin’. Recently, another plant hormone ‘Cytokinin’ has gained prominence for its involvement in the grain revolution in rice and other field crops. Suo moto homeostasis of CK by the cytokinin oxidase enzyme governs the cardinal shoot apical meristem that produces new flowering primordia thereby enhancing grain number. Similarly, the flowering hormone ‘Florigen’ impacts sympodia formation, flowering, and fruit production in tomato. The role of heterozygosity induced heterosis by florigen in revolutionizing tomato production and cellular homeostasis of CK by CK oxidising enzyme (CKX) in enhancing rice production has been path-breaking. This review highlights role of phytohormones in grain revolution and crop specific fine-tuning of gibberellins, cytokinins and florigen to accomplish maximum yield potential in field crops.
•Hormonal control of important agronomic traits through research gave rise to green revolution in rice and wheat.•We highlight intrinsic role of phytohormone mediated green revolution that averted an imminent world hunger in 1960s.•The impact of tinkering gibberellins, auxin, cytokinins and cytokinin oxidase in revolutionizing grain yield has been discussed.•Recently, florigen has shown to increase the yield of crops in a dramatic way by breaking the yield plateau in vegetable crop tomato.•Heterozygosity induced heterosis phenomenon by "Florigen" and its dramatic impact on yield in tomato has been discussed.•We charted out a path for tinkering the plant hormones for future use to feed the ever-increasing world population.
Heterosis and inbreeding depression was analysed using a set of diallel crosses involving 10 diverse parents (excluding reciprocals). Heterosis over standard parent for grain yield per plant ranged ...from -9.65–45.45 (%) and -14.78–12.05 (%) under normal and late sown conditions, respectively and heterosis over better-parent for grain yield per plant ranged from -26.43–70.77(%) and -32.16–12.05(%) respectively. Nature and magnitude of heterosis and inbreeding depression varied across crosses, characters as well as environments. Considering the very high degree of heterosis in desirable direction, the importance of non-additive components of genetic variance was observed for yield and most of the yield contributing components. Cross II (K 603 × Azad) and cross IV (RD 2618 × PL 708) revealed better specific cross combinations to be used for heterosis. The study revealed good scope for commercial exploitation of heterosis as well as isolation of pure lines among the progenies of heterotic F1 for improvement of yield levels in barley.
Wheat (Triticum aestivum L.) is the most important crop for human nutrition that underpins the food safety of Saudi Arabia. The investigation here was to determine heterosis effects using different ...genetic methods: heterosis over better, mid parents, the genetic advance, and genotype, phenotypic coefficient of variation for estimation some traits among six wheat landraces and their F1 hybrids. In 2019, these landraces were sown using hand and after 100 days, the emasculation and crossing were made among these six landraces using hand emasculation of anthers. In 2020, seeds for these genotypes (six wheat landraces and their F1) were sown under normal irrigation accordingly done in 2019. The results showed that the most important parent was Mabia resulted with the highest value in number of tiller/ plant, 1,000-grain weight, and fresh shoot weight. The highest value of plant height among six parents was Naqra while highest value at the same trait among F1 hybrids was P3 XP6. The estimations of heterosis showed that out of 15 crosses, one cross (P1XP5) was significantly better yield than all crosses for these four traits. The genotype coefficient of variation (GCV) ranged from 12.5% to 8.7% while phenotypic coefficient of variation ranged from 17.7% to 11.3%. The correlationcoefficients was found between fresh shoot weight and number of tiller and plant height and umber of tiller. Wild wheat still serve as a source of useful germplasm with proven adaption and productivity and thus assembles of the wild wheat assortments are the initial step of breeding program.
The present study was conducted at six Basma tobacco production centres, viz. Esencay, Endikpinar, Uzumlu, Karayaka, Evciler and Yenice in 2016 and 2017. The aim was to find the best stable hybrid ...Basma tobacco lines with attributes desired by the growers and buyer firms. Four hybrid lines and their parents were used as the plant material of the study. Plant height, leaf width, leaf length, yield, grade index characteristics were investigated and nicotine, glucose, fructose, chlorogenic acid and rutin analyses were performed with an HPLC system. Genotype stabilities were determined with regard to yield and grade index. Attribute means, regression coefficient (b), regression constant (a), coefficient of determination (r2), coefficient of variation (CV%) and standard deviation of regression (S2d) were used as the stability parameters. As the average of six locations, plant height was 109.22 cm, number of leaves was 28.34, leaf width was 12.09 cm, leaf length was 22.71 cm, yield was 1612.2 kg/ha, grade index was 64.10%, nicotine content was 1.69%, glucose content was 4.54%, fructose content was 5.07%, chlorogenic acid content was 388.32 ppm and rutin content was 607.05 ppm. Hybrids had greater leaf width, leaf length, yield and chemical attributes than the parents. Significant differences were observed in all of the investigated parameters. H2 (dry leaf yield: 1808.6 kg/ha, grade index 66.20%) hybrid was identified as the most stable and promising registration candidate hybrid.
Summary
Heterosis, or hybrid vigour, is a predominant phenomenon in plant genetics, serving as the basis of crop hybrid breeding, but the causative loci and genes underlying heterosis remain unclear ...in many crops. Here, we present a large‐scale genetic analysis using 5360 offsprings from three elite maize hybrids, which identifies 628 loci underlying 19 yield‐related traits with relatively high mapping resolutions. Heterotic pattern investigations of the 628 loci show that numerous loci, mostly with complete–incomplete dominance (the major one) or overdominance effects (the secondary one) for heterozygous genotypes and nearly equal proportion of advantageous alleles from both parental lines, are the major causes of strong heterosis in these hybrids. Follow‐up studies for 17 heterotic loci in an independent experiment using 2225 F2 individuals suggest most heterotic effects are roughly stable between environments with a small variation. Candidate gene analysis for one major heterotic locus (ub3) in maize implies that there may exist some common genes contributing to crop heterosis. These results provide a community resource for genetics studies in maize and new implications for heterosis in plants.
Abstract
Admixture with archaic hominins has altered the landscape of genomic variation in modern human populations. Several gene regions have been identified previously as candidates of adaptive ...introgression (AI) that facilitated human adaptation to specific environments. However, simulation-based studies have suggested that population genetic processes other than adaptive mutations, such as heterosis from recessive deleterious variants private to populations before admixture, can also lead to patterns in genomic data that resemble AI. The extent to which the presence of deleterious variants affect the false-positive rate and the power of current methods to detect AI has not been fully assessed. Here, we used extensive simulations under parameters relevant for human evolution to show that recessive deleterious mutations can increase the false positive rates of tests for AI compared to models without deleterious variants, especially when the recombination rates are low. We next examined candidates of AI in modern humans identified from previous studies, and show that 24 out of 26 candidate regions remain significant, even when deleterious variants are included in the null model. However, two AI candidate genes, HYAL2 and HLA, are particularly susceptible to high false positive signals of AI due to recessive deleterious mutations. These genes are located in regions of the human genome with high exon density together with low recombination rate, factors that we show increase the rate of false-positives due to recessive deleterious mutations. Although the combination of such parameters is rare in the human genome, caution is warranted in such regions, as well as in other species with more compact genomes and/or lower recombination rates. In sum, our results suggest that recessive deleterious mutations cannot account for the signals of AI in most, but not all, of the top candidates for AI in humans, suggesting they may be genuine signals of adaptation.
This study was carried out at Qlyasan location in Sulaimani region (Lat 35 º 34' 307''; N, long 45º 21' 992; E, 765 masl) for F3 generation of seven pea varieties (1-Avolla, 2-Americana, 3-Jeza, ...4-Joneor, 5-Packland, 6-Arvena and 7-Samara). The seeds of 21 F3 crosses and their parents were sown in Completely Randomized Block Design (CRBD).With three replicates. The results showed that the mean squares of genotypes, gca and sca were highly significant for seed weight plant-1 and most its important components. The parents Americana and Jeza recorded maximum values for all studied characters. The cross AvollaxAmericana recorded the highest value for seed weight plant-1 and pod weight plant-1. The cross AvollaxPackland had the highest value for heterosis due to seed weight plant-1 122.114% and whole plant weight 147.111%. The parent Americana recorded maximum positive gca effect value for seed weight plant-1 and some its components pod length, pod weight plant-1 and 100-seed weight. The crosses JezaxArvena recorded maximum positive sca effect value for seed weight plant-1, while the cross AvollaxArvena showed maximum positive sca effect value for pod length and pod plant-1. The average degree of dominance was more than one for all characters indicating to the importance of non additive gene effect in controlling the inheritance of these characters. Heritability in broad sense was high for seed weight plant-1 and some its components pods number plant-1, pod weight plant-1 and 100-seed weight, while it was low in narrow sense for all characters.
Effective panicle numbers (PNs) and Tiller numbers (TNs) are important traits affecting rice (Oryza sativa L.) architecture and grain yield. However, the molecular mechanisms underlying PN and TN ...heterosis remain unknown in rice. In addition, new PN- or TN-related genes need to be detected and discovered. In this study, in order to detect rice quantitative trait loci (QTLs) and the heterosis-related loci of PN or TN in rice, we developed a high generation recombinant inbred line (RIL) population from a cross of two elite cultivars, Luohui9 (Xian/Indica) and RPY geng (Geng/Japonica), and two testcross hybrid populations derived from the crosses of RILs and two cytoplasmic male sterile lines, YTA (Xian/Indica) and Z7A (Geng/Japonica). Finally, nine QTLs of PN across four seasons were identified, and two QTLs of TN in 191HB were mapped. Besides this, six heterosis-related QTLs of PN and five heterosis-related QTLs of TN were located. We found that heterosis-related QTLs of PN or TN covered multiple known genes, such as MOC1, TAC1 and OsETR2. Furthermore, homologous gene analysis identified one candidate gene of PN (LOC_10g25720). Together, these findings uncover multiple heterosis-related loci, and provide a new insight into the heterosis mechanism of PN and TN in rice.
The anemone type, featuring prominent and colored in tubular florets, is an attractive flower shape in chrysanthemums and, thus, desired by breeders and consumers. Understanding the genetic basis of ...anemone type flowers in chrysanthemum is crucial for breeding success. The current study conducted nine cross combinations from seven parents to investigate segregation patterns, parental effect, and the relationships between the heterosis of six tubular floral traits and parental genetic distance. Significant (
P
< 0.05) differences among the parents and crosses in various tubular floral traits and transgressive segregation was observed in both directions for most traits. The broad-sense heritability of the tubular floral traits varied from
h
B
2
= 0.47 to 0.92 across different crosses. The considerable variation occurred for almost floral traits, thus indicating the substantial potential for selecting lines with the desirable traits. The segregation ratio of anemone to non-anemone followed 3:1 in anemone × anemone crosses and 1:3 in either non-anemone × anemone or anemone × non-anemone crosses, except for two reciprocal crosses derived from the parents ‘Nannong Xuefeng’ and ‘QX096’. The F
1
hybrids’ performance was more inclined towards a vulnerable parent and involved less influence of maternal or paternal effects, displaying some extended declines and negative mid-parent heterosis (MPH). The phenotypic genetic distance was significantly negatively correlated with MPH for floral traits except for style length and disk flower diameter. In contrast, we observed no significant correlation between molecular marker-based genetic distance and MPH for all floral characteristics. The findings of the current work provide insights into the complex inheritance pattern of flower types and help achieve desirable improvement in anemone type chrysanthemums.
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