A gene producing one to nine flowers per flowering node in chickpea

Chickpea (Cicer arietinum L.) has a racemose type of inflorescence and at each axis of the raceme usually one or two and rarely three flowers are borne. Plants producing 3 to 9 flowers, arranged in acymose inflorescence, at many axis of the raceme, were identified in F₂ of an interspecific cross ICC 5783 (C. arietinum) × ICCW 9 (C. reticulatum)in which both the parents involved were single-flowered. A spontaneous mutation in one of the two parents or in the F₁was suspected. However, the possibility for establishment of a rare recombination of two interacting recessive genes could not be ruled out. The number of pods set varied from 0 to 5 in each cyme. Inheritance studies indicated that a single recessive gene, designated cym, is responsible for cymose inflorescence. The allelic relationship of cym with sfl, a gene for double-flowered trait, was studied from a cross involving multi flowered plants and the double-flowered line ICC 4929. Thecym gene was not allelic to sfl, suggesting that two loci control the number of flowers per peduncle in chickpea. The cym locus segregated independently of the locus sfl, ifc (inhibitor of flower color) and blv (bronze leave). This revised version was published online in August 2006 with corrections to the Cover Date.     

Inheritance of flower colour and flavonoid pigments in Gerbera

The flower colour of Gerbera, an important ornamental cut flower, is derived from carotenoids and flavonoids. The knowledge of enzymological and genetic control of flavonoid biosynthesis is still incomplete. The present paper summarizes the results obtained at our institute between 1981 and 1993. The material for the investigation of phenotypic segregation and segregation of flavonoids after chromatographic analysis came from 408 progenies of controlled crosses. Phenotypic segregation analysis showed acyanic genotypes to be homozygous recessive and recessive epistatic over cyanic genotypes, respectively. This was confirmed by the existence of two loci controlling steps in biosynthesis (fht, dfr or ans) showing recessive mutants and complementary gene action after crosses. Flavone formation is effected by one dominant allele (fns⁺); dominant and recessive genotypes are now available. Regarding anthocyanidin inheritance, an unusual epistasis of 4′-hydroxylation (pelargonidin formation) over 3′,4′-hydroxylation (cyanidin formation) was observed. Final proof of the postulated gene actions will come from enzymological and molecular biological investigations of the chemogenetically defined Gerbera genotypes now available.     

The inheritance of chemical phenotype in Cannabis sativa L. (II): Cannabigerol predominant plants

This paper aims to clarify the genetic mechanism that is responsible for the accumulation of cannabigerol (CBG) in certain phenotypes of Cannabis sativa L. CBG is the direct precursor of the cannabinoids CBD, THC and CBC. Plants strongly predominant in CBG have been found in different fibre hemp accessions. Inbred offspring derived from one such individual were crossed with true breeding THC predominant- and CBD predominant plants, respectively. The segregations in the cross progenies indicate that CBG accumulation is due to the homozygous presence of a minimally functional allele, tentatively called B₀, at the single locus B that normally controls the conversion of CBG into THC (allele B_T) and/or CBD (allele B_D). The fact that CBG accumulating plants have so far been found in European fibre hemp populations that are generally composed of B_D/B_D plants, and the observation that the here investigated B₀ allele possesses a residual ability to convert small amounts of CBG into CBD, make it plausible that this B₀ is a mutation of normally functional B_D. Therefore, B₀ is considered as a member of the B_D allelic series encoding a CBD synthase isoform with greatly weakened substrate affinity and/or catalytic capacity.     

Inheritance of tree and fruit characters in progenies from crosses of sweet cherry (Prunus avium L.) cultivars

Summary Approximately 1000 seedlings from 20 combinations crossed in 1979, 1980 and 1981 (Theiler-Hedtrich 1985a) were tested for several characters: fruit set (yield), fruit size, fruit colour, formation of abscission layer and bleeding after fruit removal from fruit stalks, bacterial canker resistance, flowering and harvesting time. From progeny of crosses with Stella as pollinator, 56% (Vittoria × Stella) and 46% (Schüttler × Stella) of the seedlings were self-compatible, of which 14 were high yielding with good fruit size and quality. From the data recorded it can be concluded:fruit set is a recessive character; only 5 to 20% of very good yielding seedlings were obtained in different progeny, even if the parental plants were both very good croppers.Fruit juice and skin colour was in most progenies ‘black’ even if they were from combinations with ‘white’ varieties, e.g., Merton Glory or Schüttler. Only from the combination Schiittler (‘white’) × Stella (‘black’), 50% of the seedlings were ‘white’; Stella therefore is heterozygous for the character of fruit juice and skin colour.Fruit size is evenly distributed in progeny with respect to the fruit size of their parent plants.Abscission layer formation and non-bleeding is a genetically complex character. In combinations where both parent plants formed fruits with complete abscission layers and which were not bleeding after fruit removal from the stalk, this character was inherited only to 50% (Vittoria × Schüttler) or 85% (Vittoria × Frühe von der Weid) in the progeny. For the genetical control of this character further studies are necessary.Bacterial canker susceptibility was evenly distributed in seedlings from all combinations even if the highly resistant cv. Vittoria was used as one parent plant, thereby not confirming the expected results of a higher proportion of resistant seedlings from combinations with Vittoria.Flowering and harvest time of the seedlings from different combinations was within the range of the parent plants. Only in the combination of Vittoria × Stella (mid-to late-ripening season) one seedling out of 99 was found to form ripe fruits two weeks earlier than the parental plants. From the seedlings tested 40 have been chosen for further evaluation or genetical studies.     

Genetics of resistance to ascochyta blight in chickpea (Cicer arietinum L.)

Summary Six chickpea lines resistant to Ascochyta rabiei (Pass.) Lab. were crossed to four susceptible cultivars. The hybrids were resistant in all the crosses except the crosses where resistant line BRG 8 was involved. Segregation pattern for diseases reaction in F₂, BCP₁, BCP₂ and F₃ generations in field and glasshouse conditions revealed that resistance to Ascochyta blight is under the control of a single dominant gene in EC 26446, PG 82-1, P 919, P 1252-1 and NEC 2451 while a recessive gene is responsible in BRG 8. Allelic tests indicated the presence of three independently segregating genes for resistance; one dominant gene in P 1215-1 and one in EC 26446 and PG 82-1, and a recessive one in BRG 8.Research paper No. 3600     

Location of genes for chlorophyll synthesis on specific arms of chromosomes in Triticum aestivum

Summary An Indian hexaploid wheat var. Pb C591 has been shown to carry gene(s) for chlorophyll synthesis on chromosome 3A (Singh & Joshi, 1979). In the present study cv. Pb.C591, its monosomic 3A and diteocentrics for 3A, 3BL and 3DL of var. Chinese Spring have been used. The F₂ segregation involving crosses between Pb.C591 as male, monosomic line 3A of Pb.C591 (female) and ditelocentrics 3A, 3BL and 3DL of cv. Chinese Spring as male and female respectively has been observed. It has been found that there are two dominant genes regulating chlorophyll synthesis in cv. Chinese Spring. These genes are located on chromosomes arms 3A and 3DS respectively.These chlorophyll synthetic genes must be the same which were postulated by Sears (1956, 1957) as the normal alleles of virescent gene v ₂ (which was located on 3BS) on chromosomes 3A(v ₁) and 3D(V ₃).     

Sources and inheritance of resistance to stemphylium leaf spot of lettuce

Summary None of the tested cultivars of lettuce was found resistant to Stemphylium leaf spot, a common disease in Israel. Within a Lactuca saligna population collected in wild lettuce in Israel, resistance was traced. Interspecific crosses of L. saligna x L. sativa were made and the mode of inheritance of resistance to this disease was studied. Resistance is apparently controlled by two genes: one dominant (Sm₁) and one recessive (sm₂).Contribution No. 1176-E 1984 series, from the ARO.     

Aluminium tolerance in lentil (Lens culinaris Medik.) with monogenic inheritance pattern

The objectives of this study were to determine genetics of Al tolerance and whether the Al tolerance observed is governed by the same gene. The lines ‘L‐7903’ and ‘L‐4602’ have been developed through breeding programme as Al‐tolerant lines. These lines showed maximum root regrowth and minimum accumulation of Al and callose as compared to sensitive genotypes (‘BM‐4’ and ‘L‐4147’). Al tolerance in the parents, F₁, F₂ and backcross generations was estimated using the regrowth of the primary root after staining and scoring of fluorescent signals. The F₁ hybrids responded similarly to the tolerant parents, indicating dominance of Al tolerance over sensitivity. The segregation ratios obtained for Al tolerance and sensitivity in the F₂ and backcross generations were 3 : 1 and 1 : 1, respectively. Test of allelism confirmed the same gene was conferring Al tolerance in both genotypes (‘L‐7903’ and ‘L‐4602’) as the F₁ was also tolerant and no segregation of tolerant : sensitive was recorded. These results indicated that Al tolerance is a monogenic dominant trait that can be easily transferred to agronomic bases through backcross breeding technique.     

Inheritance and Correlation of Self-Compatibility and other Yield Components in the Apricot Hybrid F1 Populations

Summary To provide genetic basis for apricot (Prunus armeniaca Lam.) breeding, inheritance and correlation of yield components including self-compatibility, self-pollinated fruiting rate, fertile flower rate, average fruit weight and fruit number per plant were studied with 5-year-old seedlings of apricot F1 hybrids from ‘Katy’ × (‘Xinshiji’, ‘Katy’ × (‘Hongfeng’ and ‘Katy’ × (‘Taianshuixing’, respectively. Using the criteria that cultivars with self-pollinated fruiting rate ≥6% were self-compatible(SC), we found that the ratios of self-compatible (SC) to self-incompatible (SI) individuals were 27:25, 9:12 and 15:19 in the above three families, respectively, and conformed to the ratio of 1:1 segregation by χ² test, indicating that the S-locus of ‘Katy’ was heterozygous and self-compatibility was dominant to self-incompatibility. Twenty-seven seedlings from the F1 population of ‘Katy’ × ‘Xinshiji’ were chosen for S-allele-specific PCR. As a result, four S-genotypes with the ratio of 10:6:4:7 were obtained, which was linear to the 1:1:1:1 ratio by χ² test. Great differences in self-compatibility degree were observed among seedlings even with the same S-genotype. In the F1 populations, a very extensive segregation in self-pollinated fruiting rate, fertile flower rate and average fruit weight was observed, and average values of these traits were lower than that of mid-parent. Therefore, these traits were confirmed to be quantitative. However, significant differences were found in broad heritability (H _b ²) of following three characters: the H _b ² of self-pollinated fruiting rate (87.1% – 91.4%) was the greatest, with the variation mainly resulted from inheritance; fertile flower rate (36.8% – 49.1%) was the least and its variation was mainly caused by environmental factors. In addition, self-pollinated fruiting rate and fertile flower rate had very significantly positive correlations with single plant yield, so both may play important roles in the determination of single plant yield. In contrast, correlation between yield and average fruit weight was not significant.     

棉子品质性状的遗传研究

本研究采用6个陆地棉亲本的Griffing双列杂交设计模式Ⅱ对5个棉子品质性状进行了Hayman双列遗传模型分析.结果表明,种子蛋白质和油分百分含量、种子蛋白质和油分指数及仁指都适合“加性—显性”模型.种子蛋白质百分含量和指数以显性效应为主且表现超显性;种子油分百分含量和指数以加性效性应为主且表现部分显性;仁指加性和显性效应都较重要,接近完全显性.在所研究的亲本中,不同性状的显、隐性基因频率,正负效应基因的比例,显、隐性基因的方向及狭义遗传力等都明显不同.