Genetic Transformation for Pod Borer Resistance in Dolichos Bean [Lablab purpureus (L.) Sweet]

Background: Agrobacterium mediated genetic transformation experiments were carried out in Dolichos bean Cv. (Konkan Bhushan) showing better regenerability. Methods: Three cry genes viz. cry1Aabc, cry1Fa1 and cry2Aa were used for the transformation each of which were linked to CaMV35S promoter and nptII gene under control of nos promoter and terminator. A vector system consisting of the disarmed hyper virulent Agrobacterium tumefaciens strain EHA-105 harboring pBinAR or BinBt3 was used. Mature embryo axis with single cotyledon was used as explant. Kanamycin as well as PCR screening was carried out to assess the transformation frequency. Progeny analysis using PCR was also carried out to assess the transgene segregation and stable transformation.Result: Kanamycin concentration of 500 mg/l was found as optimum for selection of a transgenic turning leaf blades albino. Among five methods of colonization used, the method employing mild injury to explant with dipping in Agrobacterium culture for 20 minutes followed by co-cultivation for 48 hours, cefotaxime washing and sowing in soil resulted in maximum survival (74.80%) associated with maximum transformation frequency through PCR analysis (2.13%). Among three cry genes, the gene cry2Aa was found the most effective in transforming Dolichos bean. The progeny analysis of transformants has shown the 3:1 mendelian segregation ratio confirming stable transformation of transgene.

Characterization of the p3-VvAGL11 Marker for Stenospermocarpic Seedlessness in Euvitis × Muscadinia Grape Hybrid Progenies

Stenospermocarpic seedlessness from Vitis vinifera L. is being introgressed into muscadine grape (Vitis rotundifolia Michx.) germplasm through the use of a cross-fertile hybrid of the two species. Recently, a sequence-tagged site (STS) molecular marker, p3_VvAGL11, has been developed which enables detection of the dominant allele controlling stenospermocarpic seedlessness in V. vinifera. This marker was evaluated in six Euvitis Planch. × Muscadinia Planch. hybrid progenies to determine its association with seedlessness in this material. The presence of the 214-bp seedlessness-associated p3_VvAGL11 allele in seedling vines resulted in a nearly 3-fold reduction in mean seed fresh weight (MSFW) and significantly reduced mean seed weight per berry (MSWB), percent berry weight composed of seed (BWCS), and mean berry weight (MBW). When the lack of lignified seed was used as the determinant of seedlessness, the p3_VvAGL11 marker was able to correctly judge seedlessness in ≈85% of the progeny. Analysis of seedlessness in the progenies was hampered by poor vigor and fruiting ability of the hybrid seedlings. The p3_VvAGL11 marker shows potential to speed the introduction of the stenospermocarpic seedlessness into Muscadinia germplasm by identifying seedless progeny at the seedling stage.

Importance of progeny testing in alfalfa breeding (Medicago sativa L.)

The objective of this paper was to assess the importance and effectiveness of progeny tests that can be used in alfalfa breeding for increased green forage yields and shoot number per plant. A total of 35 alfalfa genotypes of different geographic and genetic origins were analyzed. The results of the study have shown that crossing full-sib or half-sib parents leads to a significant increase in yield and shoot number per plant. Significant inbreeding depression was observed in the S1 progenies of all the genotypes involved. The choice of alfalfa parents must be based on progeny analysis. Which particular method will be used will depend on the objective of the breeding program.

Influence of water chemistry and migratory distance on ability to distinguish progeny of sympatric resident and anadromous rainbow trout (Oncorhynchus mykiss)

Otolith Sr:Ca ratios near primordia (Sr:CaCore) have been used to distinguish progeny of resident and anadromous Oncorhynchus mykiss and to estimate rates of exchange between the two forms; however, the influences of confounding variables on Sr:CaCore have not been quantified. We analyzed Sr:CaCore in juvenile O. mykiss produced at 13 California hatcheries that spawn primarily resident or anadromous broodstock. Mean Sr:CaCore of progeny of resident females increased with increasing Sr:Ca ratio of the stream (Sr:CaWater) in which the mother spawned (r2 = 0.71). Mean Sr:CaCore of progeny of anadromous females averaged 1.0 × 10–3 higher, also increased with Sr:CaWater, and decreased with increasing migratory difficulty (distance × elevation) of the mother (r2 = 0.96). Model results predict that discrimination of sympatric progeny is equally good among streams where Sr:CaWater is less than 5 mmol·mol–1, but limited at higher Sr:CaWater or when anadromous females return to freshwater 6 months or more before spawning (e.g., summer steelhead). The models also provide an alternative method of interpreting Sr:CaCore data that can improve discrimination between sympatric progeny. Analysis of adults from one stream and eight hatchery sites suggested that resident females made little or no contribution to populations of anadromous adults, but anadromous females contributed to populations of resident adults.

Heterorhabditis baujardi sp. n. (Rhabditida: Heterorhabditidae) from Vietnam and morphometric data for H. indica populations

A survey of entomopathogenic nematodes in Vietnam yielded several Heterorhabditis isolates. The majority belonged to H. indica; their morphometrics are given in this paper. Three isolates collected in forests in Backan, Ninhbinh and Kontum provinces, Vietnam are here described as a new species Heterorhabditis baujardi sp. n. The new species is distinguished from the other ten valid Heterorhabditis species by a combination of morphological, morphometrical, and DNA characters. Heterorhabditis baujardi sp. n. is morphometrically similar to H. indica, but can be separated from this species by the shape of the gubernaculum and the number of normal pairs of genital papillae. The gubernaculum of H. baujardi sp. n. with the proximal end ventrally curved resembles that of H. bacteriophora. Heterorhabditis baujardi sp. n. can be separated from this latter species by a shorter body length of infective juveniles and longer spicules, longer gubernaculum, and a higher spicule length to anal body diameter ratio of males. The canonical discriminant analysis of morphometrical characters of both infective juveniles and males failed to discriminate Heterorhabditis baujardi sp. n. from H. indica. However, the new species was easily distinguished from H. downesi, H. marelatus, H. megidis and H. bacteriophora. Heterorhabditis baujardi sp. n. was slightly separated from H. bacteriophora by variables of the infective juveniles, but was clearly distinguished by variables of the males. Cross-breeding tests using isolates of the new species and H.indica did not yield fertile progeny. Analysis of the ITS1 sequence of rDNA of H. baujardi sp. n. revealed substantial differences with other known ITS1 Heterorhabditis sequences. Phylogenetic relationships between Heterorhabditis species and the usefulness of morphological and molecular characters for identification of species from this group are discussed.

Meiotic Deletion at the BUF1 Locus of the Fungus Magnaporthe grisea Is Controlled by Interaction With the Homologous Chromosome

The Magnaporthe grisea BUF1 gene suffers high-frequency mutation in certain genetic crosses, resulting in buff-colored progeny. Analysis of 16 buf1 mutants arising from a cross with a mutation frequency of 25% revealed that, in every case, the BUF1 gene was deleted. The deletions occurred in only one of the parental chromosomes and were due to intrachromosomal recombination. Tetrad analysis revealed that deletions occurred in 44% of meioses and usually affected both chromatids of the mutable chromosome. This suggests that they happen before the premeiotic round of DNA synthesis. However, they were also almost entirely restricted to heteroallelic crosses. This, together with the discovery of numerous repetitive elements that were present only in the mutable BUF1 locus, suggests that the deletion process is sensitive to pairing interactions between homologous chromosomes, such that only unpaired loci are subject to deletion. Given that karyogamy is not supposed to occur until after premeiotic DNA replication in Pyrenomycetous fungi such as M. grisea, this latter observation would place the time of deletion during, or after, DNA synthesis. These conflicting results suggest that karyogamy might actually precede DNA replication in Pyrenomycetous fungi or that parts of the genome remain unreplicated until after karyogamy and subsequent chromosome pairing have taken place.