F2 Seeds Research Articles

Prospects for interspecific hybridization of Lupinus atlanticus Gladst. with L. cosentinii Guss.

Successful crossing is reported between L. atlanticus Gladst. (2n = 38) and L. cosentinii Guss. (2n = 32), using lines of both species selected for crossability followed by selection of relatively fertile progenies. In one cross, 82E75, from a single F2 segregating plant, 22 F3 seeds were obtained. Some other less crossable combinations were completely sterile in the f1 or F2. Backcrossing to both parent species was successful, but some crosses gave relatively more seed by using F2 plants for backcrossing rather than F2's. It is concluded that potential exists for introgression of useful genes in both directions.

Inheritance of low linolenic acid content of the seed oil of a mutant in Glycine max

Linolenic acid content of the oil from F1, F2, and F3 seeds was compared with the parental values from a cross between a soybean cultivar with high (7.0%) and a mutant line with low (3.4%) linolenate (18∶3). Linolenic acid content of F1 seeds was intermediate to that of selfed seeds from the two parents and values from reciprocal crosses were essentially the same. This demonstrated that in this cross, linolenic acid content of the oil was controlled by the embryo rather than by the maternal parent. The distribution of linolenic acid in F2 seeds from F1 plants was trimodal and extended across the range of parental values. High and low linolenate F2 plants bred true for 18∶3 content and the F3 distribution of seeds from F2 plants with intermediate levels of 18∶3 was similar to the F2 distribution. The data were consistent with a model for two alleles with additive effects at a single locus controlling percent linolenic acid in these progenies. The simply-inherited alleles for low linolenate could be readily transferred to agronomically superior soybean cultivars, which would improve the fatty acid composition of the oil.

Inheritance of High Oleic Acid in Sunflower1

A sunflower (Helianthus annuus L.) oil which is high in oleic acid could be used as a cooking oil for deep fat frying of potato chips and other snack foods. Individual half‐seed analysis was used to select for high oleic acid in the high oleic sunflower cultivar Pervenets which exhibited inter‐ and intra‐plant variation for oleic acid content of individual seeds. The plant selection Pervenets‐3 and progenies bred true, remained nearly temperature insensitive, and had an average oleic content of 875 g kg−1 in six diverse greenhouse and field environments. Pervenets‐3 progenies were crossed to P21, a line which varied from 110 to 710 g kg−1 oleic acid content depending on environment. The F1 data indicates that Pervenets‐3 progenies carry a dominant factor with essentially no maternal effects which conditions high oleic acid. However, 8.9% of F1 seeds in eight of fifteen crosses exhibited deviation below 700 g kg−1 oleic content, thus indicating the presence of modifiers. The high oleic character reacted as a single dominant factor in F2's and backcrosses involving two P21 lines. In F2's from a cross involving another P21 line, one population fit the expected ratio for a single dominant factor while two populations exhibited a reversal in dominance. Apparently, some P21 lines do and some do not carry major factors and/or modifiers causing deviation. This high oleic character may be transferred to inbred lines for use in production of high oleic sunflower hybrids but low oleic parents should be selected which do not carry factors causing deviation.

Inheritance of Bruchid Resistance in Cowpea1

This study was undertaken to elucidate the nature of inheritance of resistance to bruchids [Callosobruchus maculatus. (F.)] in cowpea [Vigna unguiculata (L.) Walp.]. The parental F1, F2, and backcross populations involving three resistant and two susceptible parents were bioassayed in the laboratory for bruchid reaction on an individual plant basis. The reaction of F1 seeds was similar to that of seeds from the maternal parent, indicating that the genotype of the maternal plant controls bruchid infestation. The F2 seeds derived from F1 plants represented the true hybrid population and the mean adult emergence was similar to that of the susceptible parents, indicating complete dominance of susceptibility. No reciprocal differences were observed. The F2 plants derived from the six crosses segregated into a ratio of 15 susceptible:l resistant, indicating digenic inheritance. These results were further supported by the backcross data. The Fl plants from the backcross involving the resistant parent segregated into a 3 susceptible:l resistant ratio, whereas those involving the susceptible parent were uniformly susceptible. These data indicate that resistance to bruchids in cowpea is controlled by two recessive genes for which symbols rcml and rcm2 are being proposed.

Inheritance of lipoxygenase-2 and genetic relationships among genes for lipoxygenase-1, -2 and -3 isozymes in soybean seeds.

The mode of inheritance of lipoxygenase-2 (L-2) in soybean seeds was determined from progeny of a cross between PI 86023 (L-2-less) and Suzuyutaka (normal) soybeans. Immunological and electrophoretic analyses of F2 and F3 seeds from the cross indicated that the absence of L-2 isozyme was due to a single allele recessive to an allele controlling the presence of the isozyme. The gene symbols. Lx2 and lx2 are assigned to the alleles for the presence and absence of L-2 isozyme, respectively. Electrophoretic analysis of a total of 474 F2 seeds from the reclprocal crosses between PI 86023 (L-2-less) and Tohoku N0.74 (L-3-less) indicated that the Lx2 locus is independent of the Lx3 locus. Electrophoretic analysis of a total of 157 F2 seeds from the cross between PI 86023 and a L-1 ?? -3-less double mutant line indicated that the Lx3 locus is independent of the Lx1 and Lx2 loci, respectively, being consistent with the no linkage between the Lx2 and Lx3 loci indicated by the analysis of F2 seeds from the former reciprocal crosses. In this study, two types of double mutant seeds were identified that lacked both L-1 and L-3, and both L-2 and L-3 isozymes at the same time. However, no double mutant seeds were identified that lacked both L-1 and L-2 isozymes, so far. The L-1.L-3-less and L-2.L-3-less double mutant seeds germinated, grew and matured normally to produce F3 seeds that lacked both L-1 and L-3, and both L-2 and L-3 isozymes, respectively.

Inheritance and mapping of isoenzymes in pea (Pisum sativum L.)

Three isoenzyme systems (amylase, esterase and glutamate oxaloacetate transaminase) were examined in seeds of pea (Pisum sativum L.) and shown to give clear variation in their band patterns on gel electrophoresis between different lines. The inheritance of these isoenzyme systems, and the location of their genes on the pea genome was investigated. Reciprocal crosses were made between lines, F2 seeds were analysed for segregation in the band patterns of the isoenzymes, and F2 plants were investigated to find linkage between the genes for these isoenzymes and genes for selected morphological markers. The results obtained showed that each of the investigated isoenzyme systems is genetically controlled by co-dominant alleles at a single locus. The gene for amylase was found to be on chromosome 2, linked to the loci k and wb (wb ... 9 ... k ... 25 ... Amy). The gene for esterase was found to be linked with the gene Br (chromosome 4) but the exact location is uncertain because of the lack of the morphological markers involved in the cross. The gene for glutamate oxaloacetate transaminase was found to be on chromosome 1 and linked with the loci a and d (a... 24... Got... 41 ... d).

Inheritance of legumin and albumin contents in a cross between round and wrinkled peas

Legumin and albumin are the fractions of pea seed proteins preferred to vicilin because of their high sulfur amino acid contents. The joint inheritance of legumin and albumin contents was studied in a cross between to contrasting lines of peas - one with high legumin and low albumin, and the other with low legumin and medium to high albumin. Single seed determinations were made in the parental, F1; F2 and backcross generations using rocket immunoelectrophoresis. In the non-segregating generations (P1, P2 and F1), legumin and albumin contents were negatively correlated (r=-≅0.50). The estimates of correlation coefficients in the segregating generations (F2, BC1 and BC2) were also about -0.5. However, the two estimates based on the round and on the wrinkled seeds separately in the F2 generation were not significantly different from zero. At least four individual round F2 seeds showed the desired recombination of high legumin with high albumin indicating that the unfavorable correlation can be broken. In this cross legumin content showed predominantly additive genetic variation whereas the dominance variance was the largest component for albumin content. A combined "relative sulfur index", proposed as a convenient measure for selection, showed a narrow sense heritability of 47%. In general these results support the view that sulfur amino acid content of peas can be improved by breeding, but that the required selection regime must take both legumin and albumin content into account.

Technique for Crossing Proso Millet1

Controlled crosses are needed to exploit the genetic potential of proso millet (Panicum miliaceum L.). Techniques used for other self‐pollinated crops resulted in low seed set. The small florets with tightly held lemma and palea make emasculation difficult prior to anthesis. In this technique the florets are mechanically stimulated by rubbing and warming them between 0800 and 0900 prior to their opening naturally. The anthers are either removed immediately or are kept moist by misting with water until they can be removed. Emasculated florets are then pollinated and a glassine bag placed on the panicle. Ten to 15 min are required to produce 2 to 5 F1 seeds. This technique yields about 80% cross‐pollinated seeds.

Genetic Analysis of a Null‐Allele for Lipoxygenase‐3 in Soybean Seeds1

This study describes a major gene which controls lipoxygenase‐3 (L‐3) activity in soybean [Glycine max (L.) Merr.]. Cultlvars ‘Wasenatsu’ (PI 417 458) and ‘Ichigowase’ (PI 205 085) were found to L‐3 by both immunological and electrophoretic methods. The inheritance of this trait was determined from progeny of crosses between Wasenatsu and either ‘Century’ or ‘Raiden’, two cultlvars that contain high levels of L‐3. Segregation ratios in F2 and F3 seeds from selfed plants indicated that absence of L‐3 was due to a single allele that was recessive to the one controlling the presence of the enzyme. Comparable results have been obtained using progeny from the cross Ichigowase ✕ PI 408 251. The latter parent contains L‐3 but lacks L‐1. We propose that the dominant allele be called Lx3, whereas the recessive one be designated lx3.

A method for Production of Experimental Quantities of Hybrid Soybean Seed

The production of F1 seeds is difficult in soybeans [Glycine max (L.) Merr.]. Hand pollinations are tedious and time consuming, and each successful pollination only produces one, two, or three seeds. A method is suggested herein for producing experimental quantities of hybrid soybean seeds by the use of two traits, genetic male sterility (ms1ms1 or ms2ms2) and green seed embryo (d1d1d2d2). The green seed embryo shows through a yellow seed coat to give the soybean seed a green phenotype that can be easily recognized. Male‐sterile maintainer lines marked with green seed embryos would be used as female parents. The male parent could be any cultivar (or strain) that has a yellow seed embryo (D,1‐, D2‐, or both) and that flowers synchronously with the female parent. Cross‐pollination would be effected by insect vectors in blocks where the male and female lines were inter planted. Yellow seeds harvested from green‐seeded, male‐sterile plants would mark F1 hybrid seeds.

Inheritance of glutenin subunits in F1 seeds of reciprocal crosses between European hexaploid wheat cultivars

Ten pairs of reciprocal crosses have been made between wheat cultivars which show differences in their glutenin subunit compositions. The F1 seed glutenin subunit composition was studied by means of polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate (SDS). The results indicate that all the high molecular weight (HMW) and medium molecular weight (MMW) subunits (from 133,000 to 65,000 daltons) are transmitted to the F1 seed generation from the parental cultivars. In accordance with the triploid nature of the heterozygous endosperm (3n) and with the maternal and paternal gene dosage ratio (2∶1) in the endosperm itself, a significant effect of maternal parent is registered when comparing pairs of reciprocal seeds. Genes coding for the glutenin subunits are expressed whatever their doses are (one, two, or three) in the hybrid endosperm; thus the glutenin subunits inheritance is consistent with the co-dominant type.For one pair of the reciprocal crosses, two MMW parental bands (MW: 71,000 and 66,000) seemed absent in the F1 seed patterns while a new band with an intermediate, apparent MW (68,000) appears. This phenomenon was observed when the glutenins analyzed by electrophoresis were previously separated from other endosperm proteins, and not when they were directly extracted from the ground seed. We assume that the extraction can cause interactions between moieties attached to the subunits and lead to the formation of a complex having an intermediate electrophoretic mobility.

Genetic Control of Seed Longevity in Soybeans1

Soybean [Glycine max (L.) Merr.] seeds have a short storage life, especially in humid, tropical environments. However, a few varieties have been identified recently that have superior seed longevity. The purpose of this study was to determine if seed longevity is under maternal plant influence as is the case with many seed characteristics.Four reciprocal crosses were made between genotypes with good and poor seed longevity. A modified accelerated ageing test, followed by evaluations of seedling emergence from soil, was used to predict seed longevity of F1 seeds for three of the four crosses; for one cross the test was repeated. Differences between reciprocal crosses were significant for all four tests. A hot water stress test was also used to predict seed longevity of reciprocal F1 seeds for two crosses; two tests were run for each cross. The difference between reciprocal F1's was significant in one of the four tests. These results suggest that the maternal plant genome can influence the longevity of soybean seed.The fact that emergence of F1 families was often different from their respective maternal parent and that pooled F2 variances (seed from individual F1 plants) were larger than pooled parental variances, suggests that the genotype of the seed also may influence it's longevity. F2 seeds were examined for differences between reciprocals for one cross. The difference, though relatively small compared to reciprocal F1 differences, was statistically significant suggesting that cytoplasmic gene action may also be involved in expression of seed longevity. Because of the large noncytoplasmimc aternal plant influence, it is suggested that selection for seed longevity be delayed at least until the F3 generation.

Segregation of high and low chymotrypsin inhibitor CI-2 content in crosses between hiproly and normal lysine barley genotypes

Half barley seeds derived from reciprocal crosses between Hiproly and the normal lysine genotypes Nordal and Welam as well as between Hiproly and CI 4362 (Hiproly isogenic sisterline) were analyzed for their content of the lysine rich chymotrypsin inhibitor named CI-2. Analysis of F1 and F2 seeds suggested that a high content of inhibitor CI-2 is inherited as a single recessive trait and confirmed the close genetic relationship between Hiproly and CI 4362. Expression of a high CI-2 content in F2 was found to be different in reciprocal crosses of Hiproly with Nordal or Welam. Screening for Hiproly segregants by dye binding was compared to analysis by the CI-2 quantification method. A good correlation was obtained and this permits the conclusion that a high CI-2 content is diagnostic for the presence of thelys gene. Quantification of CI-2 in half seeds is useful for breeding towards an increase in this lysine-rich protein.

Evolution of resistance to Rhynchosporium secalis (Oud.) Davis in barley composite cross II

Changes in resistance to scald disease which occurred in barley composite Cross II over 45 generations were analyzed genetically. This population, which was synthesized in 1929 by pooling equal numbers of f1 seeds from 378 pair wise crosses among 28 barley varieties, has subsequently been grown at Davis, California under standard agricultural conditions without conscious selection. Progenies derived from self-pollinated seeds from random plants taken from four generations (F8, F13, F23, and F45) were tested against four different races of scald (40, 61, 72, and 74), and rated as resistant, susceptible or segregating. Striking increases in the frequency of families resistant to races 40, 61, and 74 occurred in CC II. A test for randomness showed that quadruply susceptible and triply resistant families were more common than expected under the assumption that resistance to different races is independent. Positive correlations were found between resistance to races 40, 61, and 74, but resistance to race 72 was independent of resistance to all other races. Possible reasons for these correlations are discussed.

A Second Edible Okra Species, and its Hybrids with Common Okra

Seventeen accessions of a West African okra species were observed in Puerto Rico, and were hybridized with the common okra species, Abelmoschus esculentus. The accessions are larger plants than common okra, but with shorter internodes. They also differ in numerous morphological and physiological characteristics. Most are more daylength sensitive than common okra. The Fi hybrids of the two species are quite sterile, although in some cases a few germinable F2 seeds are produced. Back-crosses, on the other hand, are more fertile than the Fx hybrids, and fertility is almost complete in the BC2. Some evidence was found of cytoplasmic interaction with chromosomes in production of sterile BC hybrids, a possibly useful tool for future use. Meanwhile, the transfer of genes from the new species to common okra appears very feasible.

Inheritance of Lipoxygenase‐1 Activity in Soybean Seeds1

The objectives of this study were to determine the mode of inheritance of lipoxygenase‐1 (L‐I) activity in soybean [Glycine max (L.) Merr.] seeds and to investigate possible linkage of the L‐1 locus with the Le (seed lectin), Spl (β‐amylase), and W1 (flower color) loci. The inheritance of L‐1 in soybean seeds was determined by crossing the two genotypes that lack L‐l, Plant Introduction (P.I.) 133226 and P.I. 408251, with soybean cultivars (‘Williams,’ ‘Forrest,’ ‘Columbia,’ and ‘Altona’) having normal L‐1 activity. All F1 seeds had L‐1 activity. F2 seeds resulting from these crosses segregated 3:1 indicating that the presence of L‐1 is inherited as a simple dominant. F3 seeds from heterozygous F2 plants also segregated 3:1. Reciprocal crosses gave the same results indicating no maternal or cytoplasmic effects on the inheritance of L‐1 activity. The genesymbol Lx1 is assigned to the allele coding for the presence of L‐1 protein and lx1 for the lack a detectable L‐1 protein. Linkage studies indicate that the Lx1 locus is not linked to the loci coding for W, Le, or Sp1.

Inheritance and mapping of storage protein genes in Pisum sativum L.

One and two-dimensional sodium dodecyl sulphate Polyacrylamide gel electrophoretic techniques have been used to follow the inheritance of legumin and convicilin subunits in crosses of various pea lines. The major legumin acidic subunits behaved as products of a single Mendelian gene with at least five different possible alleles. Independent segregation of a minor “big” legumin acidic subunit and the acidic and basic subunits of “small” legumin were observed, suggesting that while the main legumin subunits are produced from a set of closely linked genes at a single locus, further weakly expressed legumin genes are present at other loci. Convicilin subunits behaved as the products of a single Mendelian gene with at least three allelic forms. Genetic analysis of F2 seeds and plants from crosses of pea lines was used to map the major legumin gene (Lg-1) to a locus near the r-tl segment of chromosome 7 and the convicilin gene (Cvc) to a locus between s and k on chromosome 2.

EXPRESSION OF RL 4137 TYPE OF DORMANCY IN F1 SEEDS OF RECIPROCAL CROSSES IN COMMON WHEAT

Germination of F1 seeds of reciprical crosses between dormant RL 4137 and four less-dormant cultivars of Triticum aestivum L. was compared. Significant reciprocal differences were obtained in all four crosses. The F1 seeds having RL 4137 as the maternal parent were more dormant than the reciprocals, indicating that the seed coat and/or endosperm have a significant influence on seed dormancy. The embryo component of seed dormancy was partially dominant since the F1 seeds with RL 4137 as pollen parent were more dormant than seeds of the less-dormant parents. The degree of dominance in the F1 seeds varied among the crosses. A selection procedure for the development of a sprouting resistant cultivar through backcrossing is discussed.

Three species groups in American trilliums as revealed by compatibility with an Asian species

American trilliums are all diploid and are classified into three groups with regard to compatibility withTrillium kamtschaticum, a single diploid Asian species: (1) Compatible pedicellate-flowered species, i.e.T. erectum, T. gleasoni, andT. vaseyi. (2) Incompatible pedicellate-flowered species, i.e.T. grandiflorum. (3) Incompatible sessile-flowered species, i.e.T. decunbens, T. luteum, T. sessile andT. stamineum. HybridsT. kamtschaticum×T. erectum flowered for the first time 9–10 years after sowing F1 seeds. The F1 were completely sterile in pollen and in seed-setting.

Genetic Studies on the Dark-germination Property of Tobacco Seeds : IV. Verification of the Double Recessive Genes Hypothesis by means of Identification of Genotypes in Segregating Generation.

In the previous reports, the authors made a hypothesis that the dark-germination property of tobacco seeds (Nicotiana tabacum L.) is governed by double recessive genes (WATANABE et al. 1977 a, b, 1979). The purpose of the presernt paper is to verify that postulation by identifying the genotypes of F2 plants from a cross between two supposed genotypes, AABB and aabb. A cross was made between a light-requiring variety, Kirigasaku and a light-indifferent variety, Xanthi. The former was assumed to have a genotype of AABB and the latter aabb. Sixty eight F2 plants were allowed to self-pollinate or crossed with Xanthi. The seeds produced by the cross were called "test cross" seeds, and referred to as R1F1 seeds. As shown in Fig.1, by a dark-germination test of these two kinds of seeds F2 plants could be classified into two groups. A group consisted of F2 plants producing F3 and R1F1 seeds which could not germinate under darkness (Group I). On the other hand, the remaining 39 F2 plants produced F3 Seeds showing varying degree of dark-germination ranging from 8.0 to 96.0 percent and R1F1 seeds from 22.0 to 97.0 percent (Group II).