Estimates Of Heterosis Research Articles

Expression of heterosis and residual heterosis for traits of earliness and yield in cross combinations of cucumber (Cucumis sativus L.) developed by introgression of indigenous and exotic sources

Manifestation of residual heterosis in the F2 generation would offer the scope, as the growers need not to get the highly priced F1 seed every year. Therefore, an attempt has been made to estimate the magnitude and direction of residual heterosis for different horticultural traits in F2 generation of cucumber so that F2 seeds may be utilized to get heterotic effect with lower cost of seed production. The present study comprised of experimental material of F1 and F2 population of 18 crosses, developed by crossing 6 lines and 3 testers. All the parents, 18 each of F1 and F2 along with the standard check Pusa Sanyog were evaluated for their comparative genetic evaluation. The analysis of data showed highly significant differences for all the traits under study. First filial generation (F1) hybrid combination LC- × K-75 (104.93, 52.43 %) followed by LC-2-2 × Poinsette (91.54, 30.78 %) exhibited maximum estimates of heterosis for their respective better parent and standard check, whereas, residual heterobeltiosis and economic heterosis was maximum in the cross combination LC-2-2 × Poinsette (67.50, 24.47 %) followed by LC-12-4 × Poinsette (64.86, 22.51 %), LC-1-1 × K-75 (63.85, 35.45 %) and LC-1-1 × Poinsette (37.90, 13.99 %) respectively. Two cross combinations viz., LC-1-1 × K-75 and LC-2-2 × Poinsette were found promising for yield and yield contributing traits in both F1 and F2 generation. Presence of hybrid vigour for fruit yield in F2 generations (residual heterosis) is attributed to additive and additive × additive gene interaction and such crosses were expected to give superior segregants, which may be handled through pedigree breeding method for further improvement.

Estimation of heterosis for seed yield and its component traits in red sweet pepper (Capsicum annuum L. var grossum Sendt) grown under protected condition

The objectives focuses on estimation of the magnitude of heterosis for seed yield and its component traits taking an example of six diverse lines (Pure and Stable) of sweet pepper (red color) which were attempted in half-diallel fashion excluding reciprocals during Kharif 2017 and evaluated with a cultivar Bombay grown in a greenhouse with natural ventilation. The analysis of variance showed significant differences among parents and crosses for all traits studied. On the basis of heterosis studies, RSPUHF-3 × RSPUHF-2 and RSPUHF-4 × RSPUHF-2 were identified highly significant cross combinations over better parent and standard check for the number of seeds per fruit, seed weight per fruit, thousand seed weight and per cent seed recovery, whereas; the crosses RSPUHF-7 × RSPUHF-1 and RSPUHF-7 × RSPUHF-4 exhibited a higher standard heterosis for seed yield per plant. This study showed a desirable heterosis over better parent and standard check for seed yield and contributing traits and can further directly be identified as a superior F1 s after their validation over different seasons for growing under protected environments or may be utilized in future breeding programmes to obtain desirable segregants for the development of trait specific superior genotypes.

Heterosis in Tomato (Solanum lycopersicum L.) for Yield and Yield Component Traits

Estimates of heterosis for F1 hybrids over mid and better parent were computed for traits that showed significant differences between genotypes on analysis of variance. Heterosis for yield components and yield was studied using 8x8 half diallel cross in tomato (Solanum lycopersicum L.). The heterosis for yield was generally accompanied by heterosis for yield components. Heterosis for marketable fruit yield per plant ranged from (-63.4%) (P3xP8) to (33.8%) (P6xP8) and (-62.5%) (P3xP8) to (52.6%) (P5xP7), for mid parent and better parent respectively. Significant heterosis over better and mid-parent was observed for all the traits. Best parent and Mid-parent heterosis (MPH) was highest and in desirable direction for number of marketable fruit per plant (29.3%; 29.2%) in crosses ( P3xP6 for both ) and pericarp thickness (46.3%; 57.6%) in crosses (P2xP6 and P4xP8), number of fruit cluster per plant (32.8%; 35.9%) in cross (P3xP6 for both), individual fruit weight (36.1%; 41.2%) in cross (P2xP8, P3xP5) and fruit diameter (28.4%; 28.3%) in cross (P3xP5; P2xP6), fruit length (23.07%; 20.4%) in cross (P2xP6 for both). Out of 28 F1 crosses, positive and desirable heterosis by 10 crosses over better parent and 17 crosses over mid-parent were observed for total fruit density in tomato. An important heterosis both in heterobeltiosis and mid-parent was recorded in marketable fruit yield in ton per hectare. From all the crosses, seven crosses revealed positive from which three crosses are the most important P2xP7 (31%), P3xP5 (20%) and P3xP6 (54%) in better parent heterosis. Similarly for mid-parent heterosis, only ten crosses out of 28 reveled positive while the rest 18 crosses showed the undesirable direction for marketable fruit yield indicating majority of the hybrids exhibited unfavorable heterotic response and only a few hybrids could be considered for selection.

Estimation of Heterosis and Combining Ability of Yield Traits in Groundnut (Arachis hypogaea L.)

Background: Groundnut, an important oilseed crop is grown in about 100 countries for oil and kernel. The kernels of groundnut also serves multiple table purposes as rough snacks to other value added product other than oil. Its importance is well experienced in the area occupied by it around the world among oilseeds in which it stands within top five. There is a constant thrust in increasing the productivity of groundnut among the cultivators seeking which the present study is taken up.Methods: L × T analysis was taken up to estimate the gene action of yield and yield contributing traits for their improvement. 5 lines viz., CO 7, ICGV 07222, VRI 6, VRI 8 and GPBD 4 and 5 testers viz.,VRI 3, Chico, Gangapuri, ICGV 91114 and ICGV 93468 were crossed to obtain 25 crosses. The L × T analysis was carried out on the biometrical data recorded. GCA and SCA variance revealed the importance of both additive and non-additive gene action of all the traits. Result: Pod yield and kernel yield per plant were governed by non-additive gene action suggesting the advancement of the generation for selection to improve these traits. The parents ICGV 07222, VRI 8, Chico and ICGV 91114 were estimated to be best combiners for the inclusion in further breeding programs. The cross ICGV 07222 × Chico, a product of good combiners was best performing and can be used to obtain superior recombinants. Standard heterosis of 27% was observed for pod yield in the groundnut crosses.

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.

Exploitation of heterosis in hybrids developed using cytoplasmic genetic male sterility (CGMS) system in pigeonpea [Cajanus cajan (L.) Millspaugh

To ascertain heterosis forty hybrids were developed from fourteen parents in a line x tester mating design during kharif, 2017-18 and tested in a Randomized Block Design with three replications during kharif, 2018-19. The analysis of variance revealed that the mean sum of squares due to lines were significant for all characters except number of seed per pod and 100 seed weight, whereas the mean sum of squares due to testers were significant for all characters except number of seed per pod and seed yield per plant. This indicates the presence of sufficient amount of variability in parents utilized for hybridization. The mean sum of squares due to lines vs testers was significant for all characters except days to flowering, days to maturity, plant height, number of seed per pod and 100 seed weight. The mean sum of squares due to parents vs hybrids as well as due to hybrids were significant for all characters. The analysis of variance further revealed that the significant difference was found among lines, tester and hybrids for all the characters. This indicates that there is good chance of exploit the heterosis from present investigation. The estimates of heterosis showed that the five hybrids CMS GT 1603 A x GTR 23, CMS GT 288 A x GTR 55, CMS GT 1603 A x GTR 97, CMS GT 1616 A x GTR 55 and CMS GT 1616 A x GTR 97 were found the most promising on the basis of per se performance, standard heterosis, mid parent heterosis and better parent heterosis. Therefore, it needs to be exploited in future breeding programme.

Combining Ability and Heterosis in Diallel Analysis of Maize (Zea mays L.) Lines

A sound breeding program for maize improvement is very important to meet the demands of the growing population. Therefore, combining ability and heterosis were studied in a 4 x 4 full diallel cross in maize for growth attributes, yield and its contributing traits. Randomized Complete Block Design (RCBD) with four replicates was used to study the general combining ability of parents, specific combining ability of F1s (including reciprocals) and heterosis of the F1s over commercial check variety on selected agronomic characters. Genotype was highly significant for all the traits studied. The combining abilities (GCA and SCA) and reciprocal mean squares were highly significant for most studied characters. The ratio of GCA/SCA was not less than unity for studied traits excepted for days to anthesis and ear height. The results indicated that the additive genetic effects were more important and played major role in studied traits. Thus, results revealed GCA effects for the parental lines (PL). Where ‘PL2’ was excellent combiner for number of tassels and cob circumference and ‘PL3’ was good combiner for days to silking and grain yield (t.h-1). While ‘PL4’ for short height. Majority of the F1s from the GCA effects showed high SCA effects. This F1 (PL2 x PL3) performed best amongst. However, several reciprocals were not desirable. Heterosis estimation was carried out using a commercial check, Oba super II. When commercial check was used, the percent heterosis especially on grain yield varied from -8.89 to 22.62%. Among the twelve F1s, nine of the crosses exhibited significant positive heterosis for grain yield (t.h-1). Those F1s that showed significant positive and/or negative desirable traits for SCA effects and significant positive heterosis could be used for varietal development in maize breeding. And conservation of those parents that exhibited high GCA effects be considered as well.

Heterosis studies using Diallel analysis in bread wheat (Triticum aestivum L.)

The present study was carried out for the estimation of heterosis and heterobeltosis in bread wheat during the year 2017-18. A diallel set of 9 x 9 was prepared by crossing nine genotypes in all possible combinations excluding reciprocals. Parents and their F1 generations were planted in RBD (randomized block design) with three replications. The observations were recorded on five randomly selected plants in parents and F1s for thirteen traits. Analysis of variances showed that significant variation is present among all the genotypes for all studied traits. The mean sums of squares due to parents as well as crosses were found highly significant for all thirteen traits, indicating the existence of substantial variation for all the traits among the genotypes as well as crosses. No any cross combination was found that exhibit significant heterosis for all the traits in the present investigation. Cross combinations namely, HD3059 × Raj3765, HD2967 ×WH1184, HD2967 × Raj3765, HD3059 × WH1184 and HD3059 × WH283 were found most promising for the grain yield per plant by showing high per se performance and heterosis over better parent. These crosses could be extensively used for developing superior segregates and better pure lines for different breeding programmes.

Crossbreeding analyses and polymorphic associations of gallinacin genes with growth traits in chickens

A simple crossbreeding experiment between Fayoumi (F) and Rhode Island Red (R) and their F1 of ½R½F and ½F½R crosses was conducted. A total number of 480 chicks produced from four genetic groups was used to estimate direct additive genetic effects (GI), maternal effects (GM) and direct heterosis (HI) for growth traits by using generalized least squares procedure. The studied traits were body weights at hatch, 2, 4, 6, 8 and 10 weeks of age and daily gains during the intervals of 0-2, 2-4, 4-6, 6-8 and 8-10 weeks of age. Candidate gallinacin genes of GAL 2, GAL 3, GAL 4 and GAL 5 were genotyped using PCR-RFLP, associating the SNP with body weights and gains.Direct additive effects were mostly significantly (P≤0.01) in favour of R breed by 7.4 to 57.9 g for body weights and by 0.8 to 1.8 g for daily gains. The estimates of maternal effect were mostly significantly (P˂0.01) in favour of R breed and ranging from 0.8 to 25.1 g for body weights and 0.5 to 2.3 g for daily gains. All the estimates for direct heterosis were positive and significant (P˂0.01) and ranged from 0.15 to 35.2 g for body weights and 0.3 to 1.5 g for daily gains.The GAL 2 gene was one homozygous genotype in the four genetic groups, while in GAL 3, GAL 4 and GAL 5 genes only one homozygous genotype in Fayoumi breed was observed. The genotypes of Gal 3 gene had significant associations with most body weights and gains (p<0.05) in R, ½R½F and ½F½R genetic groups. The genotypes of GAL 4 and GAL 5 genes were associated significantly with most body weights and daily gains during the intervals of 0-2 and 2-4 weeks of age in½R½F and ½F½R genetic groups. In practice, the molecular associations obtained for GAL 3, GAL 4 and GAL 5 genes could be used in marker assisted selection programs to improve growth traits in chickens.

Estimates of heterosis and combining ability of soybean diallel crossings

This study aimed to estimate the general and specific combining ability of partial soybean diallel crossings. The parents were divided in two groups contrasting for the characteristics of mass of thousand seeds, maturity group, flowers’ color, lodging and growth aspect. The scheme of partial diallel followed the Griffing model, where it were included the parents and the F1 generation. There was predominance of additive genic effects for the characteristics number of seeds per pods, number of seeds per plant and plants height. For number of pods per plant, seeds per plant and mass of hundred seeds the dominance effects were expressed by the superiority of specific combining ability in the determination of these characters. The parents G3 and G7 were the ones that contributed the most to the increase in yield in function of general combining ability for the characters number of pods per plant, seeds per plant, plant yield and mass of hundred seeds. The hybrids from the crossings between G3 x G5 and G3 x G4 are more promising for the characteristics related to yield, since they present elevated heterosis effect and high specific combining ability associated to increase general combining ability presented by the parent G3.

Heterosis for seed cotton yield and yield contributing traits cotton (Gossypium hirsutum L.)

Estimation of heterosis is very important to spot out the promising hybrid combinations for commercial exploitation of heterosis and to identify the best segregants to develop varieties. The objective of this study was to estimate the heterosis of all types i.e. mid parantal heterosis, heterobeltoisis and standard heterosis for yield contributing parameters. Nine genotypes and 20 F1 hybrids developed by crossing the parental genotypes in L x T design were sown in a randomized complete block design along with RCH 659 as standard check. It was observed that the line × tester interactions made greater contribution to the total variance for yield and its attributes. Proportional contribution of lines to total variance was very low for all the traits, while testers also followed similar pattern and contributed a minimum to the total variance. However, maximum variance was extended by line x tester interaction for all the yield contributing traits studied. Out of 20 hybrids, the cross combinations namely, TCH1716 × L 765, TCH1716 × L 766, GSHV179 × L 765 and F 2453 × L 766 were accompanied by significant and positive heterosis for number of bolls per plant, boll weight, number of sympodia per plant and lint index besides seed cotton yield per plant. It indicated larger scope for heterosis breeding for commercial exploitation of heterosis. The crosses that shown desirable heterosis over standard check can be advanced for isolation of improved lines for different yield contributing traits.

Estimation of combining ability and heterosis by using diallel mating design in Kabuli genotypes of chickpea

An experiment consisting of six parents and 15 hybrids (developed by using 6 x 6 half diallel mating design) in kabuli chickpea was laid out in RBD design with three replications to estimate combining ability and heterosis. The ANOVA (Analysis of Variance) for different characters revealed highly significant differences among genotypes for all traits under study.The estimates of SCA variance were found to be higher than the GCA variance for all the characters under consideration, indicating good prospects for exploitation of non-additive gene action for grain yield and its components under study. Estimates of the ratio of gca variances to the sca variances for all the characters is less than one indicating the preponderance of non-additive gene effects (dominance and epistasis) in controlling the expression of all the characters under study. Line KAK2 was identified as good general combiner for plant height, canopy width, number of secondary branches per plant, number of pods per plant, pod length, grain yield per plant, biological yield per plant, 100 seed weight and harvest index. High estimates of heterosis over better parent, mid parent and standard check was exhibited by three crosses viz., PKC1 × HK4, KAK2 × HK4 and JGK1 × HK4.

The heterosis estimates for growth and survival traits in sterlet and Siberian sturgeon purebreds and hybrids

The aim of the present study was to estimate and compare the growth and survival traits of the hybrids and purebreds produced by crossing the Siberian sturgeon (Acipenser baerii) (S) and sterlet (Acipenser ruthenus) (St) in order to determine the heterosis effect in the F1 generation. We compared the breeding conditions, mean body weight (BW) and cumulative survival in the artificially produced hybrid crosses of sterlet and Siberian sturgeon with respect to their pure parental species in indoor and outdoor aquaculture systems at different developmental stages. Fertilization and hatching rates were found to be significantly higher in S × S purebred compared to St × S hybrid. The highest values of BW were recorded in St × S hybrid (557.54 ± 179.7 g) on 862 days post-hatch (dph) while the highest cumulative survival was recorded in S × S purebred (14.3%). The recorded cumulative survival and mean BW was significantly lower in St × St purebred. The highest positive heterosis was recorded for mean BW of St × S hybrid (51.3% on 862 dph) throughout the sampling points. The studied sturgeon hybrids had higher mean BW compared to St × St purebred under suboptimal rearing conditions. Although there was no clear demonstration of the superiority in performance of reciprocal hybrids over purebreds, the St × S hybrid can be used for achieving better productivity in aquaculture systems.

Development of heterotic hybrid in bitter gourd (Momordica charantia L.) for earliness and high fruit yield

The present investigation was undertaken to study the magnitude of heterosis in 45 hybrids (F1s) developed by following the Line × Tester mating design using fifteen lines and three testers for earliness and high fruit yield. Among the parents, OBGCBR-2 and IC-085611 have performed as superior genotypes for heterosis. Highest degree of heterosis for most of the traits i.e., earliness and fruit yield traits were registered in desired direction in the hybrid OBGCBR-2 × Jaunpuri Green. Estimation of standard heterosis in cross OBGCBR-1 × IC-085611 recorded desired relative heterosis for days to 50% pistillate flowering. Heterosis for node at which 1st pistillate flower appears was in the desired direction in cross OBGCBR-2 × Jaunpuri Green for standard check and; hybrid Meghna × Jaunpuri Green for relative heterosis and heterobeltiosis. Hybrids Katehi × IC-085612 exhibited negative and significant relative heterosis and heterobeltiosis for internodal length. In case of sex ratio and fruit length cross OBGCV-2 × IC-085612 showed heterosis in desired direction for relative parent and heterobeltiosis. The positive and significant, relative parent and heterobeltiosis was in the hybrid Green Jhalari × Jaunpuri Green for fruit diameter. For average fruit weight positive and significant heterosis observed in cross OBGCBR-2 × IC-085611 over standard parent. Estimation of standard heterosis for number of fruit plant-1 indicated that the hybrids OBGCBR-2 × IC-085611 found to be desirable superior cross combinations over standard heterosis followed by Meghna × Jaunpuri Green for relative parent and heterobeltiosis.

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.

Combining Ability Analysis , Estimation of Heterosis and Some Genetic Parameters Using Half Diallel Cross in Bread wheat (Triticum aestivum L.)

Combining Ability Analysis , Estimation of Heterosis and Some Genetic Parameters Using Half Diallel Cross in Bread wheat (Triticum aestivum L.)

Esimation of heterosis in mungbean [Vigna radiata (L.) Wilczek

The present investigation on “Estimation of Heterosis in Mungbean [Vigna radiata (L.) Wilczek]” was conducted during Kharif 2016-17 using four line and six tester making 24 crosses and evaluation this material using Randomized Block Design. The cross combination BPMR 145 x BM 2011-1 recorded the highest standard heterosis over the check BM 2003-2. The cross BM 4 x TBM 9 exhibited the highest significant mid parent heterosis and heterobeltosis for the number of pods per plant. The cross AKM 8802×BM 2011-1 was found highest standard heterosis for pod length, number of pod per plant and grain yield per plant. The study further can used to breed a genotype with high yielding potential and to collect the information on the genetic mechanism controlling various traits in the material.

Estimation of heterosis for yield and its components under normal and sodic soil in barley (Hordeum vulgare L.)

Manipulation of heterosis is considered to be a vital approach to enhance the yield potential of barley and is as accepted to be a safe strategy to overcome barriers in barley yield. Thirteen diverse Indian genotypes were crossed to obtain a series of crosses to estimate the level of heterosis and heterobeltiosis among F1 hybrids along with their parents under two contrasting environments: normal and sodic soil. Estimates revealed a significant relationship between the mean performance of F1 hybrids and their parents under sodic stress regime only. The presence of significant heterosis for grain yield was also accompanied by heterosis for yield components, such as days to 50% flowering, plant height, number of effective tillers /plant, number of spikelets /spike, number of grains/ spike, days to maturity,1000- grain weight, biological yield / plant, grain yield / plant and harvest index. The cross NDB 1245 X NDB 943 was an elite cultivar and showed significant heterobeltiosis. The study suggests that the obtained hybrids surpassed their better parents’ effects, indicative of commercial heterosis, and are thus candidates for the commercial production of hybrid barley.

Combining Ability, Components of Genetic Variance and Heterotic Response in Faba Bean (Vicia faba L.)

The present investigation was carried out at the Students’ Instructional Farm, Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya to evaluate a line x tester set of 45 hybrids (F1’s) and their 18 parents alongwith two checks for twelve characters. Forty-five crosses were constituted in Rabi, 2016-2017, whereas parents and crosses were evaluated in a yield trial in Rabi 2017-2018, in a randomized complete block design of three replications. Results revealed highly significant variations within parents and F1 genotypes indicating a wide genetic variability for the studied characters and the possibility of genetic improvement using such genetic material of faba bean. Parents, HB 10, HB 50, EC 454751 and EC 301470 showed desirable and significant GCA effects for grain yield per plant and some of the yield contributing traits to emerge as valuable donor parents for hybridization programme. Out of forty-five, eleven crosses emerged with positive and significant SCA effects for grain yield per plant. The high estimates of genotypic and phenotypic coefficient of variation and high heritability in broad sense alongwith high genetic advance in per cent of mean were recorded for number of pods per plant. A wide range of variation in the estimates of heterobeltiosis and standard heterosis in positive and negative direction was observed for grain yield per plant as well as remaining eleven traits. In case of grain yield per plant, heterobeltiosis ranged from -35.75 to 100.74 per cent, standard heterosis varied from -35.10 to 46.30 per cent over SV1 (HFB 1) and from -33.26 to 50.46 per cent over SV2 (Vikrant).

Estimation of heterosis in maize hybrids in Dang district of Nepal

Estimation of heterosis in maize hybrids in Dang district of Nepal