Hybrid Breeding (hybrid + breeding)

Distribution by Scientific Domains

Selected Abstracts

Modulation of F1 hybrid stature without altering parent plants through trans-activated expression of a mutated rice GAI homologue

Ning Su
Summary Hybrid breeding, by taking advantage of heterosis, brings about many superior properties to the F1 progeny. However, some properties, such as increased plant height, are not desirable for agronomic purposes. To specifically counter the height increase associated with hybrid progeny, we employed an Arabidopsis model and tested a trans-activation system for specifically expressing a mutated GAI gene only in the F1 hybrid plants to reduce plant stature. A transcriptional activator, the Gal4 DNA-binding domain fused to the acidic activation domain of herpes simplex virus VP16 protein, driven by a maize ubiquitin promoter, was introduced in one parental line. A rice GAI homologue with an N-terminal deletion of the DELLA domain, driven by a promoter that is responsive to the transcriptional activator, was transferred into another parental line. After genetic crossing, trans-activation of the GAI mutant gene resulted in a dwarf phenotype. Over 50 pair-wise crosses between the parental lines were performed, and analyses suggested that the percentage of F1 progeny exhibiting dwarfism ranged from about 25% to 100%. Furthermore, the dwarfism trait introduced in F1 progeny did not seem to affect total seed yield. Our result suggests the feasibility of manipulating F1 hybrid progeny traits without affecting parent plants or the agronomic property of the progeny. [source]

Heterosis for yield and other agronomic traits of winter triticale F1 and F2 hybrids

PLANT BREEDING, Issue 4 2001
G. Oettler
Abstract Triticale is generally treated as a self-pollinating crop and line breeding is practised. Hybrid breeding has been discussed for some time, but there is little information for winter triticale. This study investigated heterosis for eight agronomic traits in F1 and F2 hybrids grown together with their parents as drilled plots in three environments. On average, grain yield heterosis was 12.5 dt/ha (a relative 10.5%) compared with the mid-parent value for F1 hybrids, and 6.2 dt/ha (5.0%) for F2 hybrids and withawide range of 4.4,17.1 dt/ha for F1 hybrids. A positive contribution to the heterosis of yield was made by kernels/spike and 1000-kernel weight, whereas spikes/m2 showed negative heterosis. Hybrid plants in F1 and F2 were taller than mid-parents (8.3 cm and 5.3 cm, respectively), with a tendency to earlier heading. The negative heterosis for falling number in F1 and F2 hybrids could be a problem for commercial production of triticale hybrids. By selecting parents for combining ability and the identification of heterotic patterns, grain yield heterosis of 20% appears feasible. [source]

Analysis of resistance mechanism to Atherigona soccata in crosses of sorghum

PLANT BREEDING, Issue 5 2009
A. Anandan
Abstract In sorghum, shoot fly resistance is important for grain yield and fodder value. An experiment was conducted to estimate genetic parameters of sorghum for resistance to shoot fly in 50 hybrids, by crossing 5 10 genotypes in line tester manner. Plant height, number of leaves per plant, number of eggs per plant, trichomes on upper and lower surface per unit area of lamina and dead heart per cent were measured on 14 and 21 days after emergence (DAE) and glossiness of leaves was graded on 14 DAE. The correlation between midparent and hybrid performance, GCA : SCA ratio revealed predominance of non-additive gene effects for the traits studied, which could be exploited through hybrid breeding. Of the parents, SPSFPR 94004A and IS 4777 were the best general combiners for shoot fly resistance. Correlation and path analysis revealed the importance of resistance traits and phenol estimation confirms the resistances against shoot fly. [source]

Trends in genetic variance components during 30 years of hybrid maize breeding at the University of Hohenheim

PLANT BREEDING, Issue 5 2008
S. Fischer
Abstract The ratio of variance due to specific vs. general combining ability (GCA) (,2SCA:,2GCA) is of central importance for predicting hybrid performance from GCA effects. The objectives of our study were to (1) analyse the changes in estimates of ,2GCA, ,2SCA and their ratio during 30 years of hybrid maize breeding and (2) compare the observed trends in genetic variances with those expected under a simple genetic model. We analysed multilocation yield trials based on the North Carolina Design II conducted in the maize breeding programme of the University of Hohenheim from 1975 to 2004 for grain yield (GY) and dry matter content (DMC). GY showed a significant (P < 0.05) annual increase of 0.17 Mg/ha, but no linear trend was found for DMC. Since the beginning of hybrid breeding at the University of Hohenheim, the sum of estimates of ,2GCA of the flint and dent heterotic groups were higher than the estimates of their ,2SCA. This predominance did not change with ongoing inter-population improvement. Consequently, superior hybrids can be identified and selected mainly based on their prediction from GCA effects. [source]

Genetic diversity among parental lines of Indica hybrid rice (Oryza sativa L.) in China based on coefficient of parentage

PLANT BREEDING, Issue 6 2006
S. Wang
Abstract Genetic diversity constitutes the raw material for plant improvement, and provides protection against genetic vulnerability to biotic and abiotic stresses. Diversity of parental lines of indica hybrid rice in China is not well-characterized. The major objective of this study was to quantify genetic diversity of Chinese parental lines of hybrid rice via coefficient of parentage (COP). All 100 parental lines of hybrid rice widely used in hybrid breeding and commercial production during 1976,2003 were studied by COP analysis. The mean COP for the 100 parental lines was low (0.056), indicating a potentially high degree of diversity in Chinese hybrid rice breeding. Forty-nine percent of all pairs of parental lines were completely unrelated by pedigree data. The low mean COP for the parental lines was attributed to a continual incorporation of exotic germplasm (wild rice, japonica and javanica etc.) into the genetic base over time, to the introduction of foreign germplasm from the Philippines (International Rice Research Institute), Korea, the United States, Thailand, and Guyana as breeding stock. The mean COP from 1976 to 1990 was twice as much as that from 1990 to 2003. Cluster analysis was an effective method to discriminate diversity, ten clusters were identified, and maintainer lines, restorer lines and other parental lines with special genetic background were clearly grouped. In addition, restorer lines were further divided into 11 sub-clusters, which basically was in agreement with hybrid rice breeding. Among ten provinces, Hunan, Sichuan and Fujian were outstanding for breeding 54 of 100 parental lines in hybrid rice production, and the genetic diversity of parental lines in Fujian, Sichuan,Guangxi, Hunan and Jiangsu were all narrower than that in Hubei, Guangdong, Zhejiang and Jiangxi. The result of coefficient of parentage analysis for 100 parental lines may promote the management of parental diversity and hybrid rice breeding in China. [source]

Resynthesis of Brassica napus L. for self-incompatibility: self-incompatibility reaction, inheritance and breeding potential

PLANT BREEDING, Issue 1 2005
Article first published online: 28 JUN 200, M. H. Rahman
Self-incompatibility (SI) in Brassica has been considered as a pollination control mechanism for commercial hybrid seed production, and so far has been extensively used in vegetable types of Brassicas. Oilseed rape Brassica napus (AACC) is naturally self-compatible in contrast to its parental species that are generally self-incompatible. Introduction of S-alleles from its parental species into oilseed rape is therefore needed to use this pollination control mechanism in commercial hybrid seed production. Self-incompatible lines of B. napus, carrying SI alleles in both A and C genomes, were resynthesized from self-incompatible B. oleracea var. italica (CC) cv.,Green Duke' and self-incompatible B. rapa ssp. oleifera (AA) cv. ,Horizon', ,Colt' and ,AC Parkland'. All resynthesized B. napus lines exhibited strong dominant SI phenotype. Reciprocal cross-compatibility was found between some of these self-incompatible lines. The inheritance of S-alleles in these resynthesized B. napus was digenic confirming that each of the parental genomes contributed one S-locus in the resynthesized B. napus lines. However, the presence of two S-loci in the two genomes was found not to be essential for imparting a strong SI phenotype. Possible use of these dominant self-incompatible resynthesized B. napus lines in hybrid breeding is discussed. [source]