Marker-assisted stacking of null Kunitz trypsin inhibitor and off-flavour generating lipoxygenase-2 in soybean

Soybean varieties genetically free from Kunitz trypsin inhibitor (KTI) and lipoxygenase-2 (Lox2) are desirable to increase human consumption, as the former is an antinutritional factor that affects protein digestibility while the latter is a principal contributor to off-flavour. In the present investigation, soybean genotypes free from both these undesirable components were developed by introgression of null allele of Lox2 from NRC109 (lox2lox2) into two KTI-free soybean genotypes derived from genotypes JS97-52 and NRC7. Foreground selection of plants in F1, F2, BC1F1, BC1F2, BC2F1 and BC2F2 generations developed from two cross combinations i.e. NRC7-derived KTI-free genotype (N7KTIF)×NRC109 (parental combination 1) and JS97-52 derived KTI free genotype (JKTIF)×NRC109 (parental combination 2) was performed using null allele specific markers and tightly linked simple sequence repeat (SSR) markers for both KTI and Lox2 genes for the identification of homozygous recessive (titilox2lox2) plants. Background selection was performed using 239 and 241 polymorphic SSR markers across the genome. This resulted in the development of 9 and 13 soybean lines stacked for null alleles of both KTI and Lox2 (titilox2lox2) exhibiting recurrent parent genome content more than 97 and 96%, respectively. Days-to-flowering, days-to-maturity, 100-seed weight and yield per plant of the stacked lines developed from both the parental combinations were at par with the respective recurrent parents.

Studies on Estimation of Heterosis for Green Yield and Contributing Attributes in Fodder Sorghum (Sorghum bicolour L.)

The present investigation was carried out during Kharif seasons of year 2013-14 and 2014-15 at the Instructional Dairy Farm of G.B. Pant University of Agriculture and Technology, Pantnagar. The experimental material was developed by mating five male sterile lines as tester parents of sorghum with eight lines in line x tester mating design. The field experiment with 55 treatments including 40 F1s, 5 CMS lines as testers, 8 pollinator lines as lines and two standard checks was planted in randomized block design with three replications during both years in kharif seasons. Among pollinators, 11A2 and M35-1 performed best with all testers. For green fodder yield, most of the crosses exhibited singnificant and positive values for batter parent and mid parent heterosis while singnificant and positive standard parent heterosis was recorded only for one cross i.e. 11A2 x UPC2 (16.34). Among all crosses, 11A2 x UPC2 performed best for most of the characters and can be recommended as potential parental combination for further testing for varietal improvement of sorghum.

Study of Per Se Performance and Heterosis for Seed Yield and Component Traits in Sesame (Sesamum Indicum L.)

The phenomenon of heterosis has provided the most important genetic tools in improving yield of crop plants. Identification of specific parental combination capable of producing the highest level of heterotic effects in F1 has immense value for commercial exploitation of heterosis. The experimental material consisted of eight parents (including check G.TIL 4) and their 28 half-diallel crosses. The analysis of variance revealed highly significant differences due to genotypes for all the traits. On the basis of mean values, the parents G.TIL 10, G.TIL 4 and SKT 1607 recorded maximum seed yield per plant. G.TIL 10 was top ranking for number of effective branches per plant. This parental genotype also expressed good performance for various yield components, viz., number of seed per capsule, harvest index (%) and oil content (%).The parent SKT 1608 found better for earliness, dwarfness and 1000 seed weight (g). While in case of hybrids, SKT 1608 × SKT 12-2, SKT 1608 × G.TIL 2 and SKT 1607 × G.TIL 2 were the best for seed yield per plant. Among the 28 F1 hybrids, SKT 1608 × SKT 12-2 and SKT 1608 × G.TIL 2 manifested significant positive heterosis for seed yield per plant over better parent and standard check (G.TIL 4) These two crosses also exhibited either of the significant positive heterosis for various component traits viz., plant height (cm), capsule length (cm), number of seed per capsule, harvest index (%), 1000 seed weight (g), oil content (%) and leaf area per plant (cm2).

Phenotyping and genotyping parents of sixteen recombinant inbred peanut populations

ABSTRACT In peanut (Arachis hypogaea L.), most agronomically important traits such as yield, disease resistance, and pod and kernel characteristics are quantitatively inherited. Phenotypic selection of these traits in peanut breeding programs can be augmented by marker-assisted selection. However, reliable associations between unambiguous genetic markers and phenotypic traits have to be established by genetic mapping prior to early generation marker-assisted selection. Previously, a nested association mapping (NAM) population of 16 recombinant inbred line populations (RILs) consisting 4870 lines was established. In order to facilitate effective mapping of such a large genetic resource, the first objective of the current study was to phenotype the parental lines for yield, pod traits, field maturity, germination, plant morphology, salt tolerance and resistance to tomato spotted wilt virus (TSWV) and late leaf spot (LLS). For most measured traits, more than one parental combination demonstrated statistically significant variation which can be further quantified and mapped in the respective RIL populations. The second objective of this study was to genotype the parental lines using the Arachis Axiom SNP arrays to reveal the marker density of the mapping populations. The Version 1 array identified 1,000 to 4,000 SNPs among the population parents and the number of SNPs doubled on the Version 2 array. Further phenotyping and genotyping of the NAM populations will allow the construction of high density genetic maps containing quantitative trait loci.

Influence of plasmogenes on the productivity of morphogenesis in strawberry (Fragaria x ananassa Duch.)

Plasmogenes are largely located in mitochondria or plastids and they can influence the inheritance of many plant characteristics. This phenomenon is called cytoplasmic inheritance and can be detected on the basis of the expression of a trait in progeny F₁ obtained from single and reciprocal crosses. The aim of this study was to examine the cytoplasmic inheritance of <i>in vitro</i> productivity of morphogenesis in three genotypes of Fragaria x ananassa Duch., i.e. the cultivars 'Dukat', 'Teresa' and the breeding clone no. 590. Single and reciprocal crosses were done according to Griffi ng's method 3. The value of general combining ability (GCA) indicated cv. 'Teresa' as the best maternal component for crossing and 'Dukat' as the worst. The negative reciprocal cross effects (r_ij) revealed the cytoplasmic inheritance for cv. 'Dukat' as maternal form and positive r_ij for the breeding clone no. 590 indicated the nuclear inheritance of morphogenetic ability. Cv. 'Teresa', as maternal component, showed nuclear inheritance of that trait in crossing with cv. 'Dukat' and with 590 cytoplasmic inheritance. The productivity of morphogenesis in strawberry depended on the parental combination and the direction of crossing.

Evaluation of Interspecific Hybrids between Lagerstroemia indica and L. speciosa

Production of viable interspecific seedlings from a cross between Lagerstroemia indica L. ‘Tonto’ × L. speciosa (L.) Pers. was confirmed by comparison of morphological traits and genetic markers. Traits such as plant height and width showed marked variation within the seedling population whereas variation in other traits such as flower size and color was very limited. Seedlings were found to be functionally sterile as either male or female parents. Observed sterility prevents the maximum introgression of important complex traits such as cold hardiness by sib mating or backcrossing into clones derived from this parental combination. ‘Princess’ was confirmed to be a sterile hybrid of L. indica and L. speciosa whereas ‘Monia’ was indicated to have L. indica in its ancestry but not L. speciosa.

SUCCESSFUL INTERSPECIFIC HYBRIDIZATION BETWEEN Kalmia angustifolia VAR. caroliniana (SMALL) FERNALD AND Kalmia latifolia L.

The genus Kalmia L. is endemic to North America. Kalmia latifolia is the best known species in the genus. It is a rounded evergreen shrub to small tree that ranges from northern Florida to New England. Flower color varies from white to pink, but at lower elevations in the southeastern U.S., pink flowers quickly fade to white. It is a diploid species with 2n = 2x = 24 chromosomes. Kalmia angustifolia var. caroliniana only occurs in the southeastern US. It is a thin upright evergreen shrub to 1.5 m tall. Flower color is either light pink or rosy purple, and the flower pigments appear to be heat stable. It is also diploid. Kalmia latifolia has not crossed readily with any other Kalmia species to date, but a small number of hybrids have been produced. The objective of the present study was to intercross K. angustifolia var. caroliniana with K. latifolia to attempt to develop color stable pink flowered Kalmia hybrids for warm climates. The crosses were made at Cary, N.C., from late April through mid May and included two clones of each species. Only one parental combination was successful and involved a rosy purple form of the former species. With this cross 15 mature seed capsules resulted from 38 pollinations. Numerous seedlings initially germinated, of which about 15% were albinos. Only 38 seedlings survived to transplanting. Thirty seedlings remain relatively vigorous 8 months after potting and are phenotypically intermediate between the parents. Their potential will depend on their ornamental characteristics once they reach maturity.

Molecular changes atRrnloci in barley (Hordeum vulgareL.) hybrids withH. bulbosum(L.)

Southern blots of restriction fragments of genomic DNAs from Hordeum vulgare (L.), H. bulbosum (L.), and interspecific hybrids and their derivatives were hybridized with rDNA probe to identify locus-specific modifications at Rrn loci. H. bulbosum rDNA revealed a single EcoRV site per repeat compared with two sites in H. vulgare rDNA repeats. H. bulbosum accessions possessed at least two rDNA repeat lengths, indicating heterozygosity at the Rrn locus. Hybrids possessed both H. vulgare and H. bulbosum rDNA repeats. Two of the hybrid derivatives possessed bulbosum-specific Sau3AI and HaeIII rDNA fragments, while amphiploid and doubled haploid derivatives lacked H. bulbosum rDNA repeat units and (or) fragments. Two hybrid derivatives, one amphiploid and a doubled haploid derived from the same parental combination, lacked the vulgare Rrn2-specific 9.0-kb rDNA repeat. This is the first conclusive evidence for the elimination of vulgare genetic material in vulgare-bulbosum hybrids. The ratios of 9.0- to 9.9-kb vulgare repeats and H. vulgare to H. bulbosum rDNA repeats indicate partial loss of the vulgare-specific 9.0-kb rDNA repeat among the hybrids. Differences in MboI and Sau3AI fragments and the ratios of 9.0 to 9.9 kb vulgare rDNA repeats revealed differential methylation at Rrn1and Rrn2loci. Hybrids and derivatives showed differential distribution of methylation of EcoRI, BglII, and SacI sites at the Rrn1locus. Two of the hybrid derivatives exhibited extensive CpG-biased methylation. Data presented here are indicative of the differences in the onset of events triggered by the interaction of the component genomes and enabled detection of differential methylation among Rrn loci, loss of H. vulgare genetic material, and development of doubled haploids with the Rrn1locus.Key words: DNA methylation, elimination, Hordeum vulgare, H. bulbosum, Rrn loci.

Genotype and Parental Combination Influence Efficiency of Cybrid Induction in Citrus by Electrofusion

Interspecific hybridizations by electrofusion of embryogenic callus cells from `Seminole' tangelo (Citrus reticulata Blanco × C. paradisi Macf.), `Hazzara (Abohar)', or `Ohta' ponkan (C. reticulata Blanco) and leaf cells from `Lisbon' lemon [C. limon (L.) Burm. f.] or rough lemon (C. jambhili Lush.), respectively, were performed. Electrofusion of `Seminole' tangelo and `Lisbon' lemon, `Hazzara (Abohar)' and rough lemon, and `Ohta' ponkan and rough lemon resulted in 33, 43, and 36 plants, respectively. Seven to 10 plants in each combination were selected randomly and used to investigate nuclear and cytoplasmic genomes. Regenerated plants derived from electrofusion of `Seminole' tangelo and `Lisbon' lemon, and `Hazzara (Abohar)' and rough lemon possessed the same restriction fragment pattern for nuclear rDNA as that of the mesophyll parents and the same mitochondrial DNA (mtDNA) restriction pattern as that of the respective suspension parents, indicating that they were cybrids. In contrast, all the plants resulting from a combination between `Ohta' ponkan and rough lemon were confirmed by nuclear rDNA and mtDNA analysis to be somatic hybrids. The analysis of chromosome number supported the results of Southern blot hybridization. The results suggest that specific cell lines, parental combinations, or both can increase the efficiency of inducing cybrids in Citrus by electrofusion.