Abnormal Embryo Development and Efficient Embryo Rescue in Interspecific Hybrids, Oryza sativa * O. minuta and O. sativa * O. officinalis.

Abstract

Interspecific hybrids between cultivated rice (Oryza sativa, 2n = 24, AA) and two wild species (O. minuta, 2n = 48, BBCC and O. officinalis, 2n = 24, CC) have been produced by cross pollination. The embryo development in these interspecific hybrids was observed to study the deterioration features in detail. All hybrids showed either abnormal embryo development with degenerating endosperm or embryo retardation itself. Abnormally developed embryos were observed by the end of 7 days after pollination and the percentage of abnormally developed embryos increased from 7 to 14 DAP. The embryos were excised at 7 to 14 DAP and cultured on MS medium supplemented with 1, 3 and 5 mg/l benzylaminopurine, 1 g/l casein hydrolysate, 0.8 % agar and 3 % sucrose. The optimal time for rescue turned out to be 11-14 DAP. There was a significant difference (P = 0.05) in the regeneration efficiency rate with rescue time but no significant difference with of culture medium in these cross combinations. The F 1 hybrids were morphologically intermediate between their parents. All F 1 hybrid plants thus obtained were completely sterile. Chromosome doubling was attempted by treating F 1 hybrid tillers with colchicine to overcome their sterility. The morphology of the colchicine-treated F 1 plants closely resembled the female parent and fertility.

Intergeneric Hybrid from Jatropha curcas L. and Ricinus communis L.: Characterization and Polyploid Induction

“…The F 1 hybrid seeds in this study however were shrunken with slimmed embryos (Figure 1), an observation that has been reported in other research [14,30]. Interspecific or intergeneric hybridization is limited by postzygotic incompatibilities including embryo abortion and degeneration, resulting in a decrease in fertility.…”

“…The reproducibility of the RAPD patterns was confirmed by repeating the PCR analysis [21,22,23]. RAPD markers have been extensively studied and successfully used for the identification and confirmation of F 1 hybrids in plant breeding [14]. The RAPD analysis is technically simple, cheap, requires little amount of DNA, produces large number of polymorphic markers, and does not require sequence information [15].…”

“…Molecular markers play a very significant role in the identification and confirmation of F 1 hybrids during plant breeding [13]. A number of molecular marker techniques have been established, among which, the randomly amplified polymorphic DNA (RAPD) has been extensively studied and successfully used in plant breeding [14]. The RAPD analysis has been widely used for studying genetic relationships among closely related species [15].…”

Crossability and evaluation of incompatibility barriers in crosses between Capsicum species

“…Empty or degenerated seeds are considered post-fertilization barriers in most crosses (Jansky 2006), possibly involving endosperm degeneration and subsequent death of the embryo (Rodrangboon et al 2002).…”

Functional Genomics For Crop Improvement

“…Embryo rescue is still being used in breeding programs for the generation of genetic variability and incorporation of desirable traits from inter-specific or inter-generic hybrids (for review see Sharma et al 1996). Embryo rescue to develop improved germplasm has been successfully used in legumes (Clarke et al 2006;Fratini and Ruiz 2006;Fratini and Ruiz 2008), cereals (Rodrangboon et al 2002;Tikhenko et al 2008), oilseed crops (Luhs and Friedt 1994;Muangprom et al 2006), horticultural crops Drew et al 2006;Yang et al 2007;Tian and Wang 2008) and many other economically important plant species. A more sophisticated approach to the creation of genetic variability was through somatic cell hybridization by fusion of protoplasts, and in the late 1970s several significant breakthroughs occurred in addition to publication of a number of reports pertaining to basic protoplast isolation and culture (for reviews see Lynch et al 1993;Waara and Glimelius 1995;Davey et al 2005;Liu et al 2005).…”