scholarly journals Genetic distance estimates among single cross hybrids and correlation with specific combining ability and yield in corn double cross hybrids

2008 ◽  
Vol 7 (1) ◽  
pp. 65-73 ◽  
Author(s):  
M. Balestre ◽  
J.C. Machado ◽  
J.L. Lima ◽  
J.C. Souza ◽  
L. Nóbrega Filho
Keyword(s):  
Genetic Distance ◽  
Combining Ability ◽  
Specific Combining Ability ◽  
Single Cross ◽  
Single Cross Hybrids ◽  
Double Cross

scholarly journals Performance of testers with different genetic structure for evaluation of maize inbred lines

2012 ◽  
Vol 42 (5) ◽  
pp. 770-776 ◽  
Author(s):  
Lauro José Moreira Guimarães ◽  
Glauco Vieira Miranda ◽  
Rodrigo Oliveira DeLima ◽  
Ciro Maia ◽  
Lucimar Rodrigues de Oliveira ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Combining Ability ◽  
Genetic Variance ◽  
Inbred Lines ◽  
General Combining Ability ◽  
Specific Combining Ability ◽  
Genetic Base ◽  
Maize Inbred Lines ◽  
Single Cross ◽  
Single Cross Hybrids

The objective of this study was to evaluate four maize testers for identification of superior inbreed lines in testcross. The four testers evaluated are cultivars with narrow or wide genetic base (single-cross hybrids and open pollinated varieties) and two kernel types (flint or dent). SynD and SynF testers are open pollinated varieties with dent and flint kernels, respectively, and FSH and DSH testers are single-cross hybrids with flint and dent kernels, respectively. SynD tester showed the biggest genetic variance among the maize inbreed lines in crosses. The effects of general combining ability (GCA) for lines and specific combining ability (SCA) for lines x testers were significant, whereas GCA effects for testers were not significant. SynD and SynF testers identified the largest number of lines with higher GCA. The DSH and FSH testers showed suitable to identify lines with high SCA. It was concluded that SynD and SynF testers are adequate to identify inbreed lines with high GCA effects, and it's possible to identify new lines with high heterotic potential in each one of the four testers.

scholarly journals Assesment of recombinant lines of maize hybrids for inbred development

2015 ◽  
Vol 43 (3) ◽  
pp. 363-366
Author(s):  
Uttam Chandel ◽  
BS Mankotia ◽  
KS Thakur
Keyword(s):  
Inbreeding Depression ◽  
Combining Ability ◽  
General Combining Ability ◽  
Specific Combining Ability ◽  
Lower Percentage ◽  
Maize Hybrids ◽  
Mating Design ◽  
Commercial Company ◽  
Single Cross ◽  
Single Cross Hybrids

Maize (Zea mays L.) breeders currently exploit genetically narrow-base populations by deriving the recombination lines from F2 of commercial single cross hybrids. A mating design was proposed for maize hybrid evaluation as source germplasm. The commercial single cross hybrids, Hi Shell, DKC 7074 and PMZ 4, developed by the commercial company, Monsanto, were evaluated for their usefulness as germplasm. According to mating design three criteria were used: the percentage of inbreeding depression, the general combining ability and the specific combining ability. PMZ 4 had a lower percentage (21.9) of inbreeding depression, which was also combined with positive general combining ability (7.5) and negative specific combining ability. The estimated percentage of inbreeding depression was greater in DKC 7074 (31.4) and in Hi Shell (25.3). DKC 7074 also had negative general combining ability (35.5), while Hi Shell had positive specific combining ability (75.0). Therefore, evaluation through mating design showed PMZ 4 possesses more desirable genes and that it’s F2 may be a more profitable germplasm for developing elite inbred lines DOI: http://dx.doi.org/10.3329/bjb.v43i3.21615 Bangladesh J. Bot. 43(3): 363-366, 2014 (December)

scholarly journals GENERAL AND SPECIFIC COMBINING ABILITY OF MAIZE TRAITS STUDIED IN SINGLE CROSS HYBRIDS

2018 ◽  
Vol 49 (6) ◽  
Author(s):  
Hussain & Hussen
Keyword(s):  
Leaf Area ◽  
Combining Ability ◽  
Block Design ◽  
Diallel Cross ◽  
General Combining Ability ◽  
Kernel Weight ◽  
Specific Combining Ability ◽  
Single Cross ◽  
Ear Height ◽  
Single Cross Hybrids

The study was carried out  using full diallel cross between six inbred lines of maize, parents and their F1 including reciprocals were planted in 19th march 2014 at field of agriculture college, Duhok University. All treatments arranged in randomized complete block design (RCBD) with three replications to estimate the general and specific combining ability of maize traits in single cross hybrids. According to the mean square values of The results showed that the general combining ability, specific combining ability, and reciprocal combining ability, the general combining ability exhibited significant variance for all traits except days to 75% tasseling and number of kernels row-1, whereas, specific combining ability was non significant for leaf area though its prerogative  for all other traits. The reciprocal combining ability was remarkable  for days to 75% tasseling, plant and ear height, leaf area, ear diameter, ear length, number of rows ear-1, number of kernels row-1, 300- kernel weight and yield plant-1. The hybrid IK8xTH613 displayed the best value for yield plant-1 and IK58XTH613 for days to 75% tasseling, while the reciprocal HSxIK8 was the best for yield plant-1.

scholarly journals Construction of a breeding parent population of Populus tomentosa based on SSR genetic distance analysis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhiqiang Han ◽  
Qiang Han ◽  
Yufei Xia ◽  
Xining Geng ◽  
Kang Du ◽  
...  
Keyword(s):  
Genetic Distance ◽  
Combining Ability ◽  
Growth Traits ◽  
Random Mating ◽  
Specific Combining Ability ◽  
Hybrid Breeding ◽  
High Fertility ◽  
Germplasm Resources ◽  
Parent Population ◽  
High Genetic Diversity

Abstract Parent selection is the core of hybrid breeding. The breeding strategy involving the parental identification of superior open-pollinated progeny of Populous tomentosa germplasm resources can significantly improve the efficiency of parental matching. However, due to some factors such as loose powdering time and pollen competitiveness, the offspring derived from open-pollination families which do not undergo completely random mating. Although hybrid combinations based on the male identification method have a high combining ability, this method cannot easily cover the mating combinations of all male and female specimens in the germplasm bank. In addition, the performance of superior plants in open-pollinated families also affects the selection result. If the trait performance value is higher than the population average, then the special combining ability of the reconstructed hybrid combination may be overestimated. Obtaining a solution to the above problems is of great significance for improving the efficiency and accuracy of selecting hybrid parents of P. tomentosa. In this study, 24 pairs of SSR (Simple Sequence Repeats) molecular markers were used to analyze the genetic differentiation of P. tomentosa germplasm resources. The results showed that the genetic variation of the P. tomentosa population was derived from individuals within the provenance, indicating that high genetic diversity is preserved in provenances. The correlation analysis showed that there was a significant positive correlation between the special combining ability of planting height and diameter at breast height (dbh) of the 34 full-sib progeny population and the genetic distance between the parents. Then, the genetic distance between 18 female plants with high fertility and 68 male plants with large pollen quantity was analyzed using this correlation. Fifteen female parents and 12 male parents were screened out, and 52 hybrid combinations with high specific combining ability for growth traits were predicted. Furthermore, for the male parent identification of superior individual plants, we constructed the breeding parent population including 10 female parents and 5 male parents, generating 14 hybrid combinations with potentially high combining ability. The results of the hybridization test showed that the specific combining ability of plant height and dbh was significantly higher than the controlled pollination. Moreover, genetic distance and paternal identification can be used to rapidly and efficiently construct hybrid parent combinations and breeding parent populations.

Assessment of tomato source breeding material through mating designs

2007 ◽  
Vol 146 (3) ◽  
pp. 301-310 ◽  
Author(s):  
M. S. KOUTSIKA-SOTIRIOU ◽  
E. A. TRAKA-MAVRONA ◽  
G. L. EVGENIDIS
Keyword(s):  
Combining Ability ◽  
Source Material ◽  
Plant Performance ◽  
Breeding Value ◽  
Population Bottlenecks ◽  
Plant Selection ◽  
Single Cross ◽  
High Yielding Varieties ◽  
Founder Events ◽  
Single Cross Hybrids

SUMMARYCultivated tomato has a narrow germplasm base because of several population bottlenecks in the form of founder events, as well as natural and artificial selections that occurred during domestication and evolution of modern cultivars. The F2 of commercial single-cross hybrids, as well as locally well-adapted varieties, provide germplasm for developing recombinant lines and exploiting genetic variability, respectively. The present study aims to discriminate the breeding value of tomato source material, i.e. commercial hybrids or well-adapted varieties, by (i) estimating tolerance to inbreeding of hybrids or estimating heterosis of diallel hybrids between varieties, (ii) determining undesirable traits and (iii) determining general combining ability (GCA) and specific combining ability (SCA) effects from diallel crosses between hybrids and between varieties. Two hybrids and four varieties were assessed. One hybrid showed 0·03 inbreeding vigour, which was not combined with undesirable traits in the F2 generation. However, negative GCA and positive SCA values did not support the hybrid as source material, provided that hybrids with low inbreeding depression, positive GCA and negative SCA correspond to an F2 capable of developing recombinant lines. The assessment of the varieties showed positive GCA and 0·34 heterosis in one variety, indicating agreement between yield and GCA, and that high-yielding varieties may produce high-yielding hybrids. In conclusion, the proposed mating design, taking into account the tolerance to inbreeding for hybrids and the heritability of general worth for both resources, provides a mechanism for ensuring continued improvement in plant performance through plant selection programmes.

scholarly journals Heterotic expression in inbreds derived from four different base populations in maize (Zea mays L.).

1970 ◽  
pp. 10-15
Author(s):  
B. Bharathiveeramani ◽  
M. Prakash ◽  
A. Seetharam
Keyword(s):  
Zea Mays ◽  
Combining Ability ◽  
Zea Mays L ◽  
Commercial Exploitation ◽  
Single Cross ◽  
Standard Heterosis ◽  
Maize Inbreds ◽  
Hybrid Mixtures ◽  
Single Cross Hybrids

The concepts of combining ability and heterosis are the fundamental tools for enhancing productivity of different crops. The main objective is to study the usefulness of inbreds derived from four different base populations namely advanced generations of single cross hybrids, three way cross hybrids, hybrid mixtures and composites by analyzing the combining ability of inbreds and crosses derived and the heterosis obtained for important characters. One hundred and forty four maize inbreds derived from four different base populations namely advanced generations of single cross hybrids, three way cross hybrids, hybrid mixtures and composites were studied for their heterotic expression. The results indicated that composite and hybrid mixture base populations shall be of great use in deriving genetically divergent inbreds and single cross hybrids with significant standard heterosis suitable for commercial exploitation.

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