High-parent Heterosis Research Articles

Practical application of heterosis on yield evidence and fruits biochemical composition for tomato (Solanum lycopersicum L.) in open ground

Relevance. The research is devoted to studying the peculiarities of the high-parent heterosis manifestation which connected with yield traits and the biochemical composition of tomato fruits.Materials and Methods. The work was carried out in 2021–2023 in open field conditions on the experimental plot of the Belarusian State Agricultural Academy (Mogilev region, Belarus). The objects of research were 30 F1 hybrids and 11 parental forms with different levels of economically valuable traits and with the specific set of genes for pathogen resistance and lycopene accumulation. The aim of the research was to create high-yield heterotic F1 tomato hybrids, adapted to open field conditions in Belarus, with a valuable biochemical composition of fruits.Results. The best hybrid combinations showed an early yield of 0.90–2.49 kg/m2, a marketable yield of 7.50–11.40 kg/m2, and a total yield of 8.22–13.12 kg/m2. High heterosis effect was established for early (88.9–291.0%), marketable (36.0–111.2%), and total (28.6–97.8%) yield in some hybrids. Significant differences in the accumulation of dry matter, carotene, and soluble carbohydrates were ascertained between the hybrids. Hybrid combinations with the highest value of true heterosis on accumulation of dry matter (18.3–21.6%), carotene (20.2–22.9%), and soluble carbohydrates (15.7–38.9%) were identified. Inheritance of early, marketable and total yield, dry matter content, carotene and soluble carbohydrates predominantly took place according to the positive overdominance, fruit weight – according to the intermediate inheritance, vitamin C content – according to the negative overdominance. Hybrids Brusnichny F1, Mansiata F1, Rada F1 were transferred to the State Inspection for Testing and Protection of Plant Varieties of the Republic of Belarus and successfully passed the testing stage in 2023.

Expression of heterosis in photosynthetic traits in F1 generation of sorghum (Sorghum bicolor) hybrids and relationship with yield traits.

Heterosis is a crucial factor in enhancing crop yield, particularly in sorghum (Sorghum bicolor ). This research utilised six sorghum restorer lines, six sorghum sterile lines, and 36 hybrid combinations created through the NCII incomplete double-row hybridisation method. We evaluated the performance of F1 generation hybrids for leaf photosynthesis-related parameters, carbon metabolism-related enzymes, and their correlation with yield traits during the flowering stage. Results showed that hybrid sorghum exhibited significant high-parent heterosis in net photosynthetic rate (P n ), transpiration rate (T r ), stomatal conductance (G s ), apparent leaf meat conductance (AMC), ribulose-1,5-bisphosphate (RuBP) carboxylase, phosphoenolpyruvate (PEP) carboxylase, and sucrose phosphate synthase (SPS). Conversely, inter-cellular carbon dioxide concentration (C i ), instantaneous water uses efficiency (WUE), and sucrose synthase (SuSy) displayed mostly negative heterosis. Traits such as 1000-grain weight (TGW), grain weight per spike (GWPS), and dry matter content (DMC) exhibited significant high-parent heterosis, with TGW reaching the highest value of 82.54%. P n demonstrated positive correlations with T r , C i , G s , RuBP carboxylase, PEP carboxylase, GWPS, TGW, and DMC, suggesting that T r , C i , and G s could aid in identifying high-photosynthesis sorghum varieties. Concurrently, P n could help select carbon-efficient sorghum varieties due to its close relationship with yield. Overall, the F1 generation of sorghum hybrids displayed notable heterosis during anthesis. Combined with field performance, P n at athesis can serve as a valuable indicator for early prediction of the yield potential of the F1 generation of sorghum hybrids and for screening carbon-efficient sorghum varieties.

Heterosis prediction of wheat based on SNP genetic distance and combining ability

<p indent="0mm">Heterosis, as a means of increasing crop yield, has been used as part of long-term strategies to meet the demand for global food security. Molecular markers have been widely used to predict the outcome of crop heterosis. However, there is little research on genomic single-nucleotide polymorphism (SNP) prediction for heterosis in wheat (<italic>Triticum aestivum </italic>L.). In this study, we genotyped 30 wheat cultivars (lines) using wheat <sc>660 K</sc> SNP chip technology and constructed the hybrid population of 419 F₁ using diallel design. Yield component traits (YCT) in three environments, combining ability effect, and the genetic distance of <sc>660 K</sc> SNP array were used to predict heterosis. As expected, general commercial heterosis (CH), mid-parent heterosis (MPH), and high-parent heterosis (HPH) were observed in wheat YCT. The combining ability effect, here composed of the general combining ability (GCA) and special combining ability (SCA), was varied due to the parents or traits. For GCA, Bainong4199 had the smallest influence on plant height (PH), while BNS366 and CL0438 had the greatest influence on thousand kernel weight (TKW) and spike length (SL), respectively. Chinese spring showed the highest GCA on PH, spike number per plant (SNPP), and grain yield per plant (GYP), and SN055525 showed the highest GCA of spikelet number per spike (SNS), grain number per spike (GNS), and kernel weight per spike (KWPS). More importantly, SN055525, Chinese Spring, and CL0438 were found to be better restorer lines for male sterile lines BNS and BNS366. In addition, when BNS, BNS366, and Zhoumai18 in the Huanghuai wheat region were crossed with Yunnanmai and MR168 in the Southwest wheat region or foreign varieties Ciava and CL0442, SCA occurred more frequently for SNPP, SL, GNS, KWPS, and GYP. GCA and SCA showed a positive correlation with hybrid yield, CH, MPH, and HPH (<italic>P </italic>&lt; 0.01). Genotyping 30 parents with <sc>660 K</sc> chips showed the genetic distance of these SNPs to be positively correlated with GYP, GCA, and CH (<italic>P </italic>&lt; 0.01). The genetic distance of SNP was greater in superior combination, and consistent with the GCAs of parents, SCA and CH in 35.71% and 61.90% among the top 10% combinations, respectively. According to the clustering results of parental SNP, YCT, and GCA, these parents were clustered into three major groups. The cultivars from the Huanghuai wheat region clustered into groups A, B1, and C2; the cultivars from the Southwest wheat region clustered in groups B2 and C1; and foreign varieties clustered in group C2. Based on the genetic distance of SNP, combining ability, and superiority combination in the Huanghuai wheat region, we propose three wheat heterotic patterns: Huanghuai group B1/Southwest group B2, Huanghuai group B1/foreign group C2, and Huanghuai group C2/group B. The male sterile lines and restorer lines can be improved based on these heterotic groups of different wheat regions, which provide an important reference for parental selection of wheat hybrids and the production and use of hybrid wheat in the Huanghuai wheat region.

Genetic dissection of heterotic loci associated with plant weight by Graded pool-seq in heading Chinese cabbage (Brassica rapa)

Four heterotic QTL and a heterozygous segment for plant weight were identified by Graded Pool-Seq, QTL-seq and traditional genetic linkage analysis in heading Chinese cabbage. Heading Chinese cabbage (Brassica rapa L. spp. pekinensis) is a cross-pollinated leafy vegetable with significant heterosis. The use of heterosis is important for breeding high-yield Chinese cabbage hybrids. However, the formation and mechanism of heterosis have not been studied. We dissected the molecular mechanism of heterosis of yield-related traits in Chinese cabbage. An F1 hybrid with high-parent heterosis of yield-related traits was selected and self-pollinated to generate segregating F2 populations. QTL-seq, Graded Pool-seq (GPS), and traditional genetic linkage analysis were used to identify four heterotic quantitative trait loci (QTL) for plant weight: qPW1.1, qPW5.1, qPW7.1, and qPW8.1. Traditional genetic linkage analysis over two years showed that qPW8.1, located in marker A08_S45 (18,172,719) and A08_S85 (18,196,752), was mapped to a 23.5kb genomic region. QTL qPW8.1 explained 8.6% and 23.6% of the phenotypic variation in plant weight and the total numbers of head leaves, respectively, and contained a heterozygous segment that might control the heterosis of plant weight. The qPW1.1 made an 11.7% phenotypic contribution to plant weight. The qPW7.1 was sensitive to environmental influence and explained 10.7% of the phenotypic variance. QTL qPW5.1 had a significant signal and was located in a genetic region near the centromere showing high heterozygosity. The "pseudo-overdominance" and "synergistic allelic" effects from parent line "XJD4" appear to play an important role in heterosis for plant weight in Chinese cabbage. These results provide a basis for an improved understanding of the molecular mechanism of yield-related traits and their heterosis.

Expression of heterosis, heterobeltiosis, and gene action in quantitative characters on soybean (Glycine max)

Abstract. Krisnawati A, Adie MM. 2022. Expression of heterosis, heterobeltiosis, and gene action in quantitative characters on soybean (Glycine max). Biodiversitas 23: 1745-1751. Most soybean (Glycine max (L.) Merrill) varieties have been created by crossing two or more parental genotypes. The study aimed to quantify the value of heterosis, heterobeltiosis, the degree of dominance as well as the gene action of the agronomic characters of F1 plants derived from the four soybean cross combinations. All the parents and crosses were evaluated in the screen house of the Indonesian Legume and Tuber Crops Research Institute (Malang, East Java, Indonesia) during 2021. The estimation for mid-parent heterosis (hMP), high-parent heterosis or heterobeltiosis (hHP), degree of dominance, and gene action was done for sevenquantitative characters (plant height, number of branches, number of nodes, number of filled pods, number of empty pods, weight of 10 seeds, and seed yield). The performance of the quantitative characters differs among cross combinations. The estimated value of heterosis mid-parent (hMP) for F1 crosses from four parental combinations ranged from -61.20 to 27.57, heterobeltiosis (hHP) ranged from -71.17 to 9.84, and the degree of dominance ranged from -6.45 to 19.40. The crosses of Derap 1 × Gepak Kuning and Dering 1 × Gepak Kuning showed a positive hMP and hHP for seed yield character. Thus, these hybrids could be used to develop high-yielding varieties with desirable traits in soybean. Seed yield character in the cross of Derap 1 × Gepak Kuning exhibited the overdominance type of gene action, meanwhile, the Dering 1 × Gepak Kuning was incomplete dominance.

Hybridization between “Haida No. 1” and Orange-shell line of the Pacific oyster reveals high heterosis in survival

In order to assess the heterosis of the hybrid between the selected lines and develop a new hybrid variety of the Pacific oyster (Crassostrea gigas) with excellent survival and growth characteristics, a diallel crosses between selected “Haida No.1” (H, 12th generation) line and Orange-shell (O, 9th generation) line of C. gigas were carried out. Heterosis for growth and survival of two parental lines (HH, H♀ × H♂ and OO, O♀ × O♂) and their reciprocal hybrids (HO, H♀ × O♂ and OH, O♀ × H♂) were systematically assessed at both larval and grow-out stages. At larval stage, the two reciprocal hybrids exhibited heterosis in both survival and growth. Compared with HH, the survival rate of OH increased by nearly 23.00% at larval stage. Moreover, the heterosis in survival (average: 35.27%) was higher than that in growth (average: 8.03%) at larval stage. During grow-out phase, reciprocal hybrids showed excellent growth and survival traits at three commercial culturing areas. The high-parent heterosis for survival of hybrids at Rushan were higher than those at Rongcheng or Huangdao. Notably, the survival rate of OH increased by nearly 32.00% compared with HH at Rushan. Among three sites, the high-parent heterosis in survival varied from 31.18% to 141.18% at day 450. Overall, OH (Orange-shell line ♀ × “Haida No. 1” line ♂) exhibited superior growth and survival traits among four crosses, which could be prioritized as a new alternative variety for commercial oyster cultivation.

Heterotic prediction of hybrid performance based on genome-wide SNP markers and the phenotype of parental inbred lines in heading Chinese cabbage (Brassica rapa L. ssp. pekinensis)

Chinese cabbage (Brassica rapa L. ssp. Pekinensis) is the most widely consumed leafy vegetable in Asia. Most commercial cultivars are F1 hybrids with high yield and good quality. To increase the breeding efficiency, heterotic prediction of hybrid performance was studied. Fourteen parental lines of Chinese cabbage were studied in a half-diallel cross to produce 91 hybrids. The average mid-parent heterosis (MPH) for 14 agronomic traits ranged from −5.07% to 106.76%, while the average high-parent heterosis (HPH) ranged from −109.90% to 80.56%. Significant HPH was observed in the growth period (−109.90%), biomass (80.56%), and plant weight (15.20%), which exhibited comprehensive advantages in breeding. Two methods were used to calculate the genetic distance (GD) between the parents based on 2,444,676 single nucleotide polymorphisms (SNPs): total SNPs (GDtotal) and homozygous differential SNPs (GDhomo). Parental clustering based on total SNPs divided the parents into three major types, namely “flat-topped”, “ovate”, and “cylindrical”. These types were more suitable for their traditional pedigree relationships. The correlation between the GD, mean parental phenotype, and heterosis indicated that the phenotype of the parental inbred lines may be useful for predicting heterosis because it is rapid and simple, whereas GD calculated using SNP markers led to a moderate improvement in heterotic prediction. GDhomo was a better predictor of heterosis and F1 performance than GDtotal. These results confirmed that whole-genome SNP markers are an effective tool for evaluating GD in Chinese cabbage and are useful for parent selection in breeding.

Heterosis study for yield and yield attributes in pearl millet [Pennisetum glaucum (L.) R. Br.

The present study was undertaken to assess the magnitude of heterosis of 28 hybrids derived from eight parents of pearl millet through diallel mating design excluding reciprocals. Hybrids exhibited from low to high significant mid parent heterosis, heterobeltiosis, and standard heterosis in desired direction for all the traits except standard heterosis for days to flowering as well as number of effective tillers per plant. The hybrid 17548 × 15388 manifested significant economic heterosis in desirable direction for grain yield per plant with plant height, test weight and protein content. The cross 15851 × 15725 also showed high heterotic magnitude over check for grain yield per plant with traits like days to flowering, days to maturity, harvest index and test weight. The heterobeltiosis for grain yield per plant ranged from -58.60 to 350.02 per cent, while the standard heterosis for grain yield per plant ranged from -61.30 to 48.72 per cent. The highest heterobeltiosis was recorded by the hybrids viz.15058 × 15725 and 15058 ×15388.

Perbaikan Sudut Daun Populasi Komposit Tanaman Jagung Melalui Hibridisasi Dengan Varietas Hibrida

This study aims to determine the average leaf angle, harvest age and yield of F1 from cross-hybrid composite; heterosis value and knowing the maternal effect of these three traits on maize. The experiment was carried out in technically irrigated rice fields from November 2019 to February 2020. The design used in this experiment was a randomized block design with two replications. The treatment was 28 F1 as a result of crossing P8IS vs NK212 and P8IS vs NK7328 and their respective reciprocal crosses. The experimental data were analyzed by means of analysis of variance and further tested with the LSD test at the 5 percent level. Heterosis values were calculated on the basis of the parents whose scores were higher (High Parent Heterosis). The t test at the 5% level was used to determine whether the maternal effect was significant. The results showed that the mean leaf angles of F1 lines from crosses and reciprocal P8IS vs NK212 were the same as the two parents; whereas the P8IS vs NK7328 cross is different. The reciprocal of cross number 13 (P8IS vs Nk7328 /R13) has smaller leaf angle than P8IS and is the same as the leaf angle of NK7328. The yield of the F1 lines from the two types of crosses was the same as each of the two parents; however, there was a tendency for an increase in yield compared to P8IS for most of the F1 lines. There was a change in leaf angle properties, harvest age and yield of F1 lines compared to one of the best parents with heterosis values are negative and positive with variations from 0.00 to 65.70 percent. Coefficient of correlation between heterosis with the average value of traits was classified as strong for the harvest age; moderate for yield and weak for leaf angle. These three traits in the two types of crosses showed no maternal effects. Smaller leaf angle, super early harvest age and higher yield, are possible to be obtained from the lines of both crosses.

Heterosis for biomass yield and other traits in ‘Alamo’ × ‘Kanlow’ switchgrass populations

AbstractHeterosis plays an important role in switchgrass (Panicum virgatum L.) breeding. To identify superior clones for hybrid development through seasonal single cut, 10 crosses derived from ‘Alamo’ × ‘Kanlow’ and parents were evaluated. The experiment was planted in 2018 using a randomized complete block design with two replications at two locations in Tennessee: the East Tennessee Research and Education Center (ETREC), Knoxville, and the Plateau Research and Education Center (PREC), Crossville. The crosses and their parents were evaluated for biomass yield, plant height, and clonal mass in the fall of 2019 and 2020. The crosses were significantly different in biomass yield within and across locations (P ≤ .05). Average biomass yield of the crosses ranged from 7.1 to 8.7 Mg ha−1 at ETREC and from 10.0 to 11.8 Mg ha−1 at PREC. The crosses demonstrated an average of 46% mid‐parent heterosis (MPH) and 24% high‐parent heterosis (HPH) for biomass yield across the two locations. The MPH and HPH were 3 and −1.3% for plant height and 12 and 1% for clonal mass, respectively. Moderate to strong positive association was found between clonal mass scores and biomass yield at individual locations across years and across locations and years (r = 0.37–0.79, P ≤ .05). The association between biomass yield and plant height was inconsistent (r = −0.24 to 0.67, P ≤ .05). The findings of biomass yield heterosis in these crosses suggested the potential of hybrid cultivars for biomass yield improvement in lowland switchgrass.

Combining Ability and Heterosis for Endosperm Carotenoids and Agronomic Traits in Tropical Maize Lines.

Provitamin A enrichment of staple crops through biofortification breeding is a powerful approach to mitigate the public health problem of vitamin A deficiency in developing countries. Twenty-four genetically diverse yellow and orange endosperm maize inbred lines with differing levels of provitamin A content were used for the analysis of their combining ability. Each inbred line was developed from crosses and backcrosses between temperate and tropical germplasm. The inbred lines were grouped into different sets according to their provitamin A levels and were then intercrossed in a factorial mating scheme to generate 80 different single-cross hybrids. The hybrids were evaluated in field trials across a range of agroecological zones in Nigeria. The effect of hybrids was significant on all the measured provitamin A and non-provitamin A carotenoids and agronomic traits. While the effect of genotype-by-environment (GxE) interaction was significant for almost all traits, it was a non-crossover-type interaction for carotenoid content. Partitioning of the variances associated with the carotenoid and agronomic traits into their respective components revealed the presence of significant positive and negative estimates of general combining ability (GCA) and specific combining ability (SCA) effects for both carotenoid content and agronomic traits. The preponderance of GCA effects indicates the importance of additive gene effects in the inheritance of carotenoid content. We found F1 hybrids displaying high parent heterosis for both provitamin A content and agronomic performance. Our study demonstrates that provitamin A biofortification can be effectively implemented in maize breeding programs without adverse effects on important agronomic traits, including grain yield.

Comparison of soft spring wheat breeding lines and F1 hybrid according to economically valuable traits

Creation of doubled haploid lines in wheat is a promising direction of research in Russia. However, the criteria for identifying good cross combinations, for which it is advisable to carry out androgenesis in vitro, have not been defined. One of these criteria could be the rate of heterosis in F1 or F2. The aim of this work was to establish the possibility of achieving the yield level of the F1 hybrid by the lines of later generations. The studies were carried out at the experimental fields of the FSBSI “Federal Altai Scientific Center for Agrobiotechnology” in 2017-2019. Varieties ‘Golubkovskaya’, ‘Omskaya 28’, ‘Saratovskaya 70’, F1 ‘Omskaya 28’ × ‘Saratovskaya 70’, F1 ‘Golubkovskaya’ × ‘Saratovskaya 70’, four breeding lines from cross ‘Golubkovskaya’ × ‘Saratovskaya 70’ and seven breeding lines from cross ‘Omskaya 28’ × ‘Saratovskaya 70’ were material for this research. Germination, survival rate, plant height, number of spikes per m2, plant biomass, number of spikelets per spike and grain per spike, 1000-seed weight, grain weight per spike and plant, harvest index, yield, duration of the “germination – ear formation” period, lodging resistance and leaf and stem rust resistance were examined. In three cases out of six, high-parent heterosis in the studied F1 hybrids was observed (yield increase – 3–19 %). Five cases of significant yield improvement in breeding lines compared to F1 hybrids were detected in 2017–2019 (additional yield 2–44 %). Lines exceeding hybrid F1 in the context of yield were taller (+5–30 cm), with more extended period “germination – ear formation” (+7–8 days), higher plant biomass (+1.24–5.16 g), a larger number of spikelets per spike (0.5–2.8 units) and larger number of kernels (+3.5–8.0 units). Pure lines of soft spring wheat can be compared in yield to F1 hybrid, from which they were obtained. This fact was possible due to the selection of lines for desired traits determined by recessive genes.

Genetic distance of maize inbreds for prediction of heterosis and combining ability

A panel of seven maize inbred lines belonging to Zemun Polje commercial pool were genotypized using SNPs bead chip. 21 hybrids, developed according to the half dialel mating design, were tested in the field together with inbred lines per se. The goal of the study was to determine the genetic distance among seven maize inbred lines and to establish whether there was a significant correlation between the genetic distance among parental inbreds and grain yield, specific combining abilities (SCA) and high-parent (HP) heterosis for the grain yield. The inbred lines ZPL2 and ZPL4 with the genetic distance of 0.487 were the most genetically distant parents, while inbred lines ZPL1 and ZPL2 with the genetic distance of 0.191 were the closest ones. Three subclusters of inbred lines were distinguished in the dendrogram. Inbred lines ZPL5, ZPL6, ZPL3 and ZPL7 were grouped into the first subcluster, while inbred lines ZPL1 and ZPL2, i.e. the inbred line ZPL4 were grouped in the second, i.e. the third subcluster, respectively. The values of the Spearman's rank correlation coefficient between the genetic distance among inbred lines based on the SNP markers, and grain yield, specific combining abilities (SCA) and high-parent (HP) heterosis were positive and statistically significant. The highest correlation coefficient was exhibited between the grain yield and high-parent (HP) heterosis (0.93), and then between the genetic distance and the grain yield (0.92) as well as between the genetic distance and high-parent (HP) heterosis (0.91).

BREEDING AND PRODUCING NEW INBRED LINES AND F1 HYBRIDS OF PICKLING CUCUMBERS

Pickling cucumber is considered one of the important types of vegetables in Egypt, but there is less interest in it; this due to the lack of hybrids charactercterized with high productivity and good commercial traits. Production can be increased through increasing genetic diversity and thus productivity via plant breeding. The present experiment was conducted at Kaha Vegetable Research Farm, Wady El- Natroon and Ismailia during 2016-2020. Six cucumber genotypes from Netherland and Sweden Gene Banks (18-CGN, 8-CGN, 16-CGN, 11-NGB, 15-CGN and 21-NGB) were selfed pollinated for 6 generations to have pure inbred lines. They crossed by half diallel method to produce 15 F1 hybrids. Evaluation of the 6 parents, 15 produced hybrids and two commercially hybrids (Livina F1 and Magdalina) was carried out for fruit length, fruit diameter, fruit weight, number of female flowers per node, node of the first female flower, number of fruits/plant and total yield/plant was done. Heterosis, heritability, inbreeding depression and number of genes controlling studied traits were estimated. The results in the cross P1 x P5 showed the highest mid-parent heterosis values for studied characters that were positive by contrast. Most high-parent heterosis values for studied characters were negative. High inbreeding depression was observed. The inbreeding depression was positively and negatively lower significant indicating the presence of vigor in F2. High estimates of narrow and broad sense heritability were observed in the cross P1 x P5, but were moderate for number of female flowers per node and node of the first female flower. Concerning number of effective genes controlling most characters were found to be 1-2 pairs of genes (or group of genes); only fruit weight and node of the first female flower traits controlled by (4) and (9) additive genes respectively.

Exploitation of Hybrid Vigor for Identification of Promising Sorghum F1 Hybrid for High Grain Yield and Resistance to Sorghum Midge

Sorghum is the second most grown cereal crop in Niger. However, sorghum production in the country is dominated by indigenous cultivars with low productivity. Productivity in grain sorghum has been achieved in developing countries around the world using hybrids. This study was conducted to evaluate heterosis in F1 sorghum hybrids for grain yield and resistance to midge. Fifty F1 sorghum hybrids were evaluated for grain yield and resistance to midge. Variation for grain yield, midge resistance, and flowering time was observed. The magnitude of better parent heterosis for grain yield and resistance to midge varied significantly among hybrids. Four hybrids combined high better parent heterosis for both grain yield and resistance to midge while eight hybrids were better than their better parent for resistance to midge. These hybrids performed well for grain yield and/or resistance to midge. Therefore, the parental lines involved in these hybrids can be advanced for commercial hybrids production or used in sorghum improvement programs.

Seed setting, combining ability and heterosis studies in gladiolus (Gladiolus grandiflorus)

The seed setting, combining ability and heterobeltiosis analysis was carried out in gladiolus (Gladiolus grandiflorus L.) based on 5 × 5 full diallel mating for different traits utilizing five genotypes, viz. ACC-15, ACC-13, ACC-11, ACC-14 and ACC-04 for the experiment. Experimental results revealed that days required for maturity of capsules, harvest percentage of capsule, number of seeds per capsule, hundred seeds weight and seed germination percentage were varied significantly among the crosses. The maximum harvestable capsules was recorded in ACC-13 × ACC- 14 and its reciprocal cross while maximum number of seeds per capsule was found in the cross ACC-15 × ACC-13. The genotypes, viz. ACC-15, ACC-11 and ACC-14 were good general combiners for most characters for many traits. ACC-04 × ACC-14 had the highest SCA effects for diameter of cormel and can be used in both yield and quality improvement. Though, most of crosses showed a negative mid-parent and high-parent heterosis, hybrids expressing the highest MPH and HPH heterosis overall, were ACC-15 × ACC-13, ACC-14 × ACC-15 and ACC-04 × ACC-14.

Supplementing selection decisions in a hybrid wheat breeding program by using F2 yield as a proxy of F1 performance

Hybrid wheat breeding programs need to use chemical hybridizing agents for seed production due to its simplicity. Alternative methods such as cytoplasmic systems or hand pollinations restrict genetic combinations or seed production which limits testing experimental hybrids in large-scale multi-environment trials (METs). Using F2 seed instead of F1 can allow programs to test hybrid cross combinations in METs and the data can be used to supplement selection decisions at early stages of breeding cycle. To test this hypothesis, two METs consisting of 40 entries were conducted in 2017 and 2018 in six locations across Texas and Nebraska. The entries included hybrids at the F2 stage and their respective parents, selected from a previous preliminary F1 evaluation experiment. In six out of 10 test environments, a F2 hybrid had statistically significant higher yield than highest yielding parent. The F2 mid-parent heterosis ranged from − 20.97 to 27.52% in 2017 and − 9.90 to 9.17% in 2018. The F2 high-parent heterosis ranged from − 21.07 to 17.85% in 2017 and − 16.57 to 6.68% in 2018. The heterosis estimates of these cross combinations at F1 stage were extracted from previous large scale METs conducted on nine environments across Nebraska and Texas in 2016–2017. A comparison of F2 heterosis from this study and F1 heterosis from the previous study revealed that F2 heterosis was highly indicative of superior F1 performance. The results provide strong evidence for utility of F2 yield data in selecting superior F1 hybrids. In addition, a practical framework for using F2 performance to aid selecting F1’s in a hybrid wheat-breeding pipeline is provided.

Heterosis and genetic diversity in the crossings of gladiolus cultivars Amsterdam and White Prosperity

Abstract Gladiolus is one of the most important and popular cut-flower bulbous in Iran. The aim of this research was to produce new, high-quality hybrids through hybridization. We generated two promising hybrids (OPRC16 and OPRC57) combination from the varieties “Amsterdam” and “White Prosperity”. The Research was conducted in Ornamental Plants Research Center in Mahallat from 2014 to 2018. Values of Hm for traits were defined as the difference between the mid-F1 value and the mid-parent value, Mean Mid-parent Heterosis (MPH) or (Hmp) and High Parent Heterosis (HPH) or (Hsp). The results showed that the morphological analysis revealed the heredity and variation in the promising hybrids. The results for the hybrid OPRC16 showed that the Hm and Hmp values were negative for peduncle length but positive for other traits. The Hsp value was observed to be negative for the traits of peduncle length, leaf width, stem diameter, and cormels diameter, but it was positive for other traits. According to the results for the hybrid OPRC57, the Hm and Hmp values were negative for plant height, floret number, peduncle length, floret diameter, stem diameter, spike length, cormles weight, and cormlet diameter and negative for other traits. Peduncle length was positive in other traits. The Hmp value was negative for peduncle length, but positive for other traits. The Hsp value was recorded to be positive for leaf length, bud diameter, vase life, cormlet number, and cormles yield but negative for other traits. All in all, OPRC57 showed a negative heterosis in most traits. Based on the results, when ‘Amsterdam’ is used as the maternal plant in crosses, it has more positive heterosis effects than when it is used as the paternal parent. These results indicate that major of traits in the phenotypic and genetic diversity coefficient was very low, indicating that they had less environmental effects, since the genotypes were cultivated under similar and controlled conditions.

EVALUASI PERFORMA PERTUMBUHAN DAN HETEROSIS PERSILANGAN ANTARA IKAN NILA NIRWANA (OREOCHROMIS NILOTICUS) BETINA DENGAN IKAN NILA BIRU (OREOCHROMIS AUREUS) JANTAN F2 PADA KONDISI TAMBAK HIPERSALINITAS

Srikandi Tilapia is one of the superior hybridized varieties between black tilapia (Oreochromis niloticus) and blue tilapia (Oreochromis aureus). This fish has fast growth and high salinity tolerance. In its development, efforts are needed to improve and improve its genetic quality. Spawning srikandi tilapia using the parent of male blue tilapia F2 (family selection) is expected to improve performance better than the previous generation.The purpose of this study was to evaluate the growth performance and heterosis value of Srikandi tilapia produced from the extraction of female Nirwana strain tilapia with male blue tilapia F2. Hatchery activities were carried out in freshwater by mass spawning method on the 25 m2 pool. Enlargement activities were carried out at brackish water pond with salinity 25–40 g / L, using net measuring 3×5×1 m3 for 120 days. The stocking density used is 15 fishes / m2. The results of this study indicate that at the final test, the hybridization of Nw ♀x Au (F2)♂ has the best performance with the average of long gain16.60 ± 0.41cm, weight gain 215.33 ± 12.19 g and survival rate 78.50 ± 02.12. Evaluation of heterosis values on the characters of length, weight, survival, and biomass showed a positive value both on the hybridization of Nw ♀x Au (F2)♂ and Au (F2)♀x NW♂. The highest high parent heterosis value for blue tilapia broodstock is shown by population Nw ♀x Au (F2)♂ with values in each character of 6.96% (length), 26.06% (weight), 2.63% (survival), 28.57% (biomass).

Estimation of heterosis and combining abilities of U.S. winter wheat germplasm for hybrid development in Texas

AbstractHybrid wheat (Triticum aestivum L.) offers promises to break the yield stagnation in global wheat productivity as a result of heterosis. But, for this promise to be realized, the level of heterosis must be adequate. To test this, elite winter wheat lines from the breeding programs of the University of Nebraska–Lincoln (UNL) and Texas A&amp;M University (TAMU) were crossed in a 25‐by‐25 full‐diallel design using a chemical hybridizing agent (CHA) to produce experimental hybrids. These hybrids were planted in a modified augmented design with commercial checks and parents at McGregor, TX, in 2016 (n = 612) and Greenville and Bushland, TX, in 2017 (n = 470) to evaluate for yield heterosis and combining ability. A subset of hybrids (n = 333) were repeated between years. The effect of field heterogeneity in grain yield was corrected by spatial modelling in ASReml‐R. Commercial heterosis ranged from −78.3 to 20.4% in 2016 and −32.9 to 6.2% in 2017. High‐parent heterosis (HPH) ranged from −70.4 to 54.3% in 2016 and −26.9 to 29.2% in 2017. General combining ability (GCA) variance was significantly higher than zero, whereas specific combining ability (SCA) variance was not. Significant maternal effect was identified in some crosses tested by computing reciprocal effects between crosses and estimating variances. This indicates that most of the heterosis is due to additive rather than dominance effect. These results suggest exploitation of GCA for higher yield while underscoring the need for development of heterotic pools to maximize SCA and dominance effects.