Effect of D-Genome Chromosome Substitutions on Hybrid Seed Development and Viability in T. turgidum var. durum X S. cereale Crosses

Triticum turgidum var. durum cv. ‘Langdon’ and the set of D-genome disomicsubstitutions in ‘Langdon’, produced at Fargo, U.S.A., were grown in a temperature controlled greenhouse and crossed with diploid spring rye (Secale cereals), to determine the effect of each substitution on 1. the crossability with rye, and 2, the viability of the resulting hybrids kernels. None of the disomicsubstitutions lines, with the possible exception of the 5D (5Bj line, gave an appreciable improvement in hybrid kernel set, -development, and -viability over the control, ‘Langdon’ The post-zygotic barrier to endosperm and embryo development, which operates in crosses between durum wheat and rye, could therefore not be suppressed by any specific chromosome of the D-genome.     

Doubled haploid production in winter wheat and triticale genotypes,using the Hordeum bulbosum system

Summary An attempt was made to produce doubled haploids on 16 winter wheat and six spring and winter triticale genotypes thought to carry genes for interspecific incompatibility. The potential for haploid production was maximized by the use of Hordeum bulbosum genotypes selected for high crossability on crossable wheat genotypes, the use of two post-pollination applications of gibberellic acid and by the pollination of immature florets.A low frequency of seed was set on both the wheat and the triticale genotypes, having mean seed sets of 0.20 per cent and 0.27 per cent respectively. Although the frequency of embryos (seed quality) was high, doubled haploid production was further limited by poor embryo differentiation and regeneration. Haploid plantlets were obtained from the wheat cultivars Moulin and Renard, although successful chromosome doubling and doubled haploid production was achieved in Moulin only.     

Crossability of tetraploid and hexaploid wheats with ryes for primary triticale production

Summary Crossability of wheat and rye was investigated during thirteen crop cycles in two contrasting locations to 1) evaluate tetraploid and hexaploid wheat parents in crosses with rye, 2) identify genotypes with high crossability and 3) assess the impact of environment on seed development. The majority of the tetraploid wheats crossed with rye had seed set around 20%, but very low embryo viability. Several wheat genotypes with seed set above 50% were identified. The hexaploid wheats crossed with rye showed poor seed set, but plant recovery was relatively high. The majority of the hexaploid wheats with highest seed set (20–30%) were from China. The results suggest differences in crossability between the rye populations, and wheat species by rye interactions. The crossability of the tetraploid and hexaploid wheats was affected by climate in the two locations.     

华北落叶松与日本落叶松种间杂交亲和性及种子形态的变异研究

【目的】探究华北落叶松×日本落叶松的种间杂交亲和性以及种子形态的变异,为育种工作和种子园建设提供科学依据。【方法】以6个华北落叶松无性系为母本,5个日本落叶松无性系为父本,通过人工控制授粉获得30个种间杂交组合的球果和杂种种子,并设置母本自由授粉试验作为对照,对种间杂交的结实性状和杂种种子长、宽、种翅长等形态性状进行测定,分析这些性状在杂交组合间及母本自由授粉间的差异。【结果】不同杂交组合间的杂交亲和性差异显著,可分为超亲、良好和较差3类,分别有2、17和11个组合;在华北落叶松×日本落叶松杂交中,种子饱满率和种子效率主要受亲本交互作用的影响,结籽率主要受母本影响;杂种种子大小与母本有关,绝大多数的种翅长度较母本更长,增幅普遍在4%以上,部分组合的增幅达到10%以上。【结论】华北落叶松×日本落叶松种间杂交有重要的育种价值,杂交育种过程中应妥善利用不同亲本组合对杂交亲和性的影响。     

同源四倍体水稻与非洲栽培稻杂交的效果

以4份同源四倍体水稻(Oryza sativa,2n=4x=48)和4份二倍体水稻(Oryza sativa,2n=2x=24)为母本,以4份非洲栽培稻(Oryza glaberrima,2n=2x=24)为父本进行远缘杂交配组,共配制32个杂交组合。研究结果表明,非洲栽培稻分别与亚洲栽培稻中的两种倍性水平的水稻品系进行杂交均表现出一定的可交配性,生殖隔离并不很严格。然而,不同倍性的亚洲栽培稻与非洲栽培稻杂交,其结实率表现出明显的差异。二倍体水稻与非洲栽培稻不容易杂交,其结实率比较低(0．32％—1．93％),而同源四倍体水稻与非洲栽培稻较容易杂交,其结实率比较高(1．22％—8．86％,)。由此认为,利用同源四倍体水稻为母本与非洲栽培稻杂交更容易将后者的遗传物质引入亚洲栽培稻。