Investigation of root phenotype in soybeans (Glycine max L.) using imagery data

Journal of Crop Science and Biotechnology - Roots are the most essential plant part owing to the uptake of water and nutrients. Therefore, phenotyping of root features is vital for improving...     

Production of prolific microsheep by embryo transfer into large non-prolific sheep

The Garole is a prolific breed of microsheep that possesses the FecB gene, which increases ovulation rate. The purpose of this study was to compare embryo production by multiple ovulation in seven Garole ewes with that in seven normal size, non-prolific Malpura ewes, and assess the influence of the large body size of Awassi crossbred recipient ewes on the birth-weight of Garole lambs. Oestrus was synchronised with two intramuscular injections of 7.5 mg prostaglandin F(2alpha) administered 10 days apart. The donor ewes were superovulated by the use of pregnant mare serum gonadotrophin and follicle-stimulating hormone. The onset and duration of oestrus were similar in both breeds. The Garole donors had higher total mean (se) ovarian responses (15.6 [3.6] v 9.1 [2.3]), ovulation rate (13.6 [3.1] v 8.4 [2.2]) and produced more transferable embryos (6.0 [3.5] v 4.0 [0.9]) than the Malpura donors, but the differences were not statistically significant. The Garole lambs produced by embryo transfer were on average 57.8 per cent heavier at birth than contemporary Garole lambs produced by natural mating.     

Electrofocusing of methanolic extracts for identification of individual flavonol biomolecules in Camellia species

An effort has been made to isolate individual catechin compounds from green tea leaves in their pure form by electrophoresis. In the present study total polyphenol extraction was carried out initially and estimated through spectrophotometric and HPLC methods. Extracted polyphenol was separated on 0.7% agarose gel and visualized at 360 nm. Fragmented individual compounds were gel eluted with methanol and confirmed as (-)-epigallocatechin (EGC), (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin gallate (EGCG) by HPLC. The method developed describes a suitable method for the isolation of valuable molecules in tea.     

Introgression from wild Cicer reticulatum to cultivated chickpea for productivity and disease resistance

Interspecific hybridization is known to improve productivity and resistance to diseases in many crops. Therefore, an attempt was made to introgress productivity and disease resistance into chickpea from wild Cicer species. The true F₁ hybrids of cultivated chickpea genotypes ‘L550’ and ‘FGK45’ with C. reticulatum were backcrossed twice to their cultivated female parents to minimize the linkage drag of undesirable wild traits. The pedigree method was followed to advance the segregating populations from straight crosses (without backcross) and BC₁/BC₂ generations to F₅–F₇. The interspecific derivatives recorded up to a 16.9% increase over the check cultivars and a 25.2% increase over the female parent in a preliminary yield evaluation trial. Of the 22 interspecific derivatives thus derived, four desi and two kabuli lines were further evaluated for seed yield in replicated trials at three diverse locations. These lines possess a high degree of resistance to wilt, foot rot and root rot diseases, and recorded a 6.1–17.0% seed yield increase over the best check cultivars.     

Cytogenetics of Brassica juncea×Brassica rapa hybrids and patterns of variation in the hybrid derivatives

Interspecific hybridization is an important tool to elucidate intergenomic relationships, transfer characters across species and develop synthetic amphidiploids, and it has been widely applied for improving Brassicas. The objective of the present study was to create genetic variability in Brassica through interspecific hybridization. Crosses between Brassica juncea (AABB, 2n= 36), and Brassica rapa (AA, 2n = 20) vars toria, yellow sarson, and brown sarson were attempted, and the hybrid derivatives were advanced to the F4 generation. Hybrids were obtained from the crosses B. juncea× toria and B. juncea× yellow sarson. The F₁ plants were vigorous and intermediate to the parents in many morphological traits. The meiotic study of AAB hybrids showed 10 II + 8 I in the majority (71.8%) of cells analysed. A maximum of 12 and a minimum of seven bivalents were also observed in a few cells. The occurrence of multivalent associations (trivalents to pentavalents) at diakinesis/metaphase I and a bridge‐fragment configuration at anaphase I were attributed to homoeology between A and B genomes. A high percentage of plants resembling B. juncea was observed in the F₂ generation. Transgressive segregation in both directions was found for plant height, primary branches, main raceme length, siliquae on main raceme, siliqua intensity, seeds per siliqua and seed yield. There were significant differences for the 14 characters in the F₄ derivatives. Moderate to high estimates of phenotypic and genotypic coefficients of variation, broad‐sense heritability, and expected genetic advance were found for seed yield, 1000‐seed weight, siliquae per plant, seeds per siliqua and days to flowering. Intergenomic recombination, reflected as wide variation in the hybrid progenies, permitted the selection of some useful derivatives.     

The impact of participatory plant breeding (PPB) on landrace diversity: A case study for high-altitude rice in Nepal

Participatory plant breeding (PPB) methods were used to develop two farmer-accepted, cold-tolerant rice varieties in Nepal — Machhapuchhre-3 (M-3) and Machhapuchhre-9 (M-9). Both were derived from the cross Fuji 102/Chhomrong Dhan. Following the introduction of these varieties, the changes in the rice landraces and varieties that farmers grew were studied in ten villages. In seven of them for which data were analysed for both 1996 and 1999, adopting farmers grew 18 landraces and four modern varieties of which three, M-3, M-9 and Lumle-2, were the products of PPB. These three varieties covered 10% of the total rice area and 33% of the rice area of the adopting farmers in the seven study villages in the 1999 survey. The adoption of the PPB varieties impacted most on the more commonly grown landraces. With the exception of two villages, the varietal richness among adopting farmers was either static or increased, and there was an overall increase in allelic diversity. However, in future, the increasing adoption of M-3 and M-9 could result in significant reductions in varietal richness, although, allelic diversity may not be greatly reduced. This revised version was published online in July 2006 with corrections to the Cover Date.     

Stay green trait: variation, inheritance and its association with spot blotch resistance in spring wheat (Triticum aestivum L.)

One thousand four hundred and seven spring wheat germplasm lines belonging to Indian and CIMMYT wheat programs were evaluated for stay green (SG) trait and resistance to spot blotch caused by Bipolaris sorokiniana during three consecutive crop seasons, 1999–2000, 2000–2001 and 2001–2002. Disease severity was recorded at six different growth stages beginning from tillering to late milk stage. SG trait was measured by following two approaches: difference for 0–9 scoring of green coloration (chlorophyll) of flag leaf and spike at the late dough stage (GS 87) and a new approach of leaf area under greenness (LAUG). Germplasm lines showed a wide range (7–89) for LAUG and were grouped into four viz., SG, moderately stay green, moderately non-stay green and non-stay green (NSG). However, very few (2.2%) lines showed high expression of SG trait, i.e., LAUG >60. LAUG appeared to be a better measure of SG trait than a 0–9 scale. Mean spot blotch ratings of SG genotypes were significantly lower than those of NSG genotypes at all growth stages. Two spot blotch resistant genotypes (Chirya 3 and Chirya 7) having strong expressions of SG trait were crossed with NSG, spot blotch susceptible cv. Sonalika. Individually threshed F₂ plants were used to advance the generations. SG trait and spot blotch severity were recorded in the parents and F₁, F₃, F₄, F₅, F₆ and F_6–7 generations under disease-protected and inoculated conditions. SG trait in the F₁ generation was intermediate and showed absence of dominance. Evaluation of progenies (202–207) in the segregating generations revealed that SG trait was under the control of around four additive genes. Lines homozygous for SG trait in F₄, F₅, F₆ and F_6–7 generations showed significantly lower mean area under disease progress curve (AUDPC) for spot blotch than those with NSG expression. A positive correlation (0.73) between SG trait and AUDPC further indicated a positive influence of SG on severity of spot blotch. The study established that variation for SG trait exists in spring wheat; around four additive genes control its inheritance in the crosses studied and there is positive association between SG trait and resistance to spot blotch.