The Effect of Intercropping of Lablab (Lablab purpureus L.) and Cowpea (Vigna unguiculata L.) at Different Planting Densities on in vitro and in sacco Dry Matter Digestibility of Napier Grass (Pennisetum purpureum)

Background: The advantage of intercropping is the more efficient utilization of the all available resources and the increased productivity compared with each sole crop of the mixture. If cowpea and Lablab intercropping with Napier grass its nutritional values was improved. Methods: The experimental design was factorial combination arrangement in randomized complete block design with three inter and intra spaces (1 m × 0.5 m, 0.75 m × 0.5 m, 0.5 m × 0.5 m) and intercropping with two tropical legumes. Treatments were T1= Pure Napier grass at 1 m row spacing, T2= Napier grass intercropped with lablab at 0.75 m row spacing, T3= Napier grass intercropped with cowpea at 0.5 m row spacing, T4= Napier grass intercropped with cowpea at 1 m row spacing, T5= Napier grass intercropped with lablab at 0.5 m row spacing, T6= Pure Napier grass at 0.75 m row spacing, T7= Napier grass intercropped with lablab at 1 m row spacing, T8= Napier grass intercropped with cowpea at 0.75 m row spacing, T9= Pure Napier grass at 0.5 m row spacing and totally nine treatments were used. Soil samples were collected before and after forage harvested. Result: Napier grass intercropped with lablab and cowpea at different planting densities had significant effect (P less than 0.05) on the in vitro dry and organic matter digestibility (IVDMD, IVOMD) and increased digestibility. The OM degradation constant was significantly different (P less than 0.05) but ‘ED’ was not and for DM degradation ‘c’ and ‘b’ were non-significant (P greater than 0.05) for Napier grass intercropped with lablab and cowpea at different planting densities. In conclusion, Napier grass intercropped with lablab and cowpea at a planting density of 24 plants m-2 was better choice for high yield and forage quality.

Phylogenetic analysis of phytochrome A gene from Lablab purpureus (L.) Sweet

Background Phytochromes are the best characterized photoreceptors that perceive Red (R)/Far-Red (FR) signals and mediate key developmental responses in plants. It is well established that photoperiodic control of flowering is regulated by PHY A (phytochrome A) gene. So far, the members of PHY A gene family remains unexplored in Lablab purpureus, and therefore, their functions are still not deciphered. PHYA3 is the homologue of phytochrome A and known to be involved in dominant suppression of flowering under long day conditions by downregulating florigens in Glycine max. The present study is the first effort to identify and characterize any photoreceptor gene (PHYA3, in this study) in Lablab purpureus and decipher its phylogeny with related legumes. Results PHYA3 was amplified in Lablab purpureus cv GNIB-21 (photo-insensitive and determinate) by utilizing primers designed from GmPHYA3 locus of Glycine max. This study was successful in partially characterizing PHYA3 in Lablab purpureus (LprPHYA3) which is 2 kb longer and belongs to exon 1 region of PHYA3 gene. Phylogenetic analysis of the nucleotide and protein sequences of PHYA genes through MEGA X delineated the conservation and evolution of Lablab purpureus PHYA3 (LprPHYA3) probably from PHYA genes of Vigna unguiculata, Glycine max and Vigna angularis. A conserved basic helix-loop-helix motif bHLH69 was predicted having DNA binding property. Domain analysis of GmPHYA protein and predicted partial protein sequence corresponding to exon-1 of LprPHYA3 revealed the presence of conserved domains (GAF and PAS domains) in Lablab purpureus similar to Glycine max. Conclusion Partial characterization of LprPHYA3 would facilitate the identification of complete gene in Lablab purpureus utilizing sequence information from phylogenetically related species of Fabaceae. This would allow screening of allelic variants for LprPHYA3 locus and their role in photoperiod responsive flowering. The present study could aid in modulating photoperiod responsive flowering in Lablab purpureus and other related legumes in near future through genome editing.

Esterco caprino na composição de substratos para germinação e emergência de Lablab purpureus

Objetivou-se avaliar a germinação, emergência e o desenvolvimento inicial do feijão Lablab purpureus, em função do efeito proporções de esterco caprino misturadas com outras fontes de substratos na produção de mudas. A pesquisa foi realizada no Departamento de Tecnologia e Ciências Sociais da Universidade do Estado da Bahia. O experimento foi conduzido em casa de vegetação, sendo os tratamentos: T1: esterco caprino curtido; T2: esterco caprino curtido + pó de serra; T3: esterco caprino curtido + substrato comercial; T4: esterco caprino curtido + areia lavada. Foi avaliada a emergência, através do seu índice de velocidade, porcentagem de emergência e ao final do experimento foram analisadas altura da planta, comprimento da raiz, diâmetro do colmo, número de folhas, massa fresca e seca da planta. Constatou-se que o tratamento esterco caprino + substrato comercial obteve-se melhor desempenho no crescimento inicial do feijoeiro.

Isolation and Screening of Quorum Quenching Rhizobacterial Isolates from the Experimental Farms of Gandhi krishi vigyana Kendra, Bengaluru, Karnataka, India

A group of synergistic bacteria that nestles on the root surface and provide a benefitting response to the plants are the rhizobacteria. The rhizobacteria benefit the plants by promoting growth and acts as biocontrol agents. Antibiosis, competition, synthesis of cell wall degrading enzymes, and eliciting induced systemic resistance are the mechanisms of biocontrol exhibited by rhizobacteria. Quorum quenching (QQ) is a new mechanism of biocontrol of pathogens whose virulence is induced by population density dependant chemical signaling. Efficient quorum quenching rhizobacteria isolated from the crop rhizospheres can be used as potential inoculums to control phytopathogens. Soft rot is one pernicious plant and storage disease affecting almost all vegetable crops. Hence, the present study was conducted to isolate rhizobacteria from the rhizospheres of six crops Rice (Oryza sativa), Maize (Zea mays), Finger millet (Eleusine coracana), Dolichos Bean (Lablab purpureus), Amaranthus (Amaranthus viridis), Field bean (Vicia faba) from the environs of GKVK. A total number of 96 rhizobacterial cultures were isolated from experimental fields of GKVK. The isolated cultures were screened for their quorum quenching ability by soft agar overlay assay and twenty-four out of ninety-six cultures were affirmative quorum quenchers. Proportionately, 25% of the total rhizobacterial isolates were quorum quenchers. The isolates were characterized morphologically and biochemically and a discussion of the obtained results are deliberately discussed.

Carboxylation Capacity Can Limit C3 Photosynthesis at Elevated CO2 throughout Diurnal Cycles

The response of carbon fixation in C3 plants to elevated CO2 is relatively larger when photosynthesis is limited by carboxylation capacity (VC) than when limited by electron transport (J). Recent experiments under controlled, steady-state conditions have shown that photosynthesis at elevated CO2 may be limited by VC even at limiting PPFD. These experiments were designed to test whether this also occurs in dynamic field environments. Leaf gas exchange was recorded every 5 min using two identical instruments both attached to the same leaf. The CO2 concentration in one instrument was controlled at 400 μmol mol−1 and one at 600 μmol mol−1. Leaves were exposed to ambient sunlight outdoors, and cuvette air temperatures tracked ambient outside air temperature. The water content of air in the leaf cuvettes was kept close to that of the ambient air. These measurements were conducted on multiple, mostly clear days for each of three species, Glycine max, Lablab purpureus, and Hemerocallis fulva. The results indicated that in all species, photosynthesis was limited by VC rather than J at both ambient and elevated CO2 both at high midday PPFDs and also at limiting PPFDs in the early morning and late afternoon. During brief reductions in PPFD due to midday clouds, photosynthesis became limited by J. The net result of the apparent deactivation of Rubisco at low PPFD was that the relative stimulation of diurnal carbon fixation at elevated CO2 was larger than would be predicted when assuming limitation of photosynthesis by J at low PPFD.

Inheritance of growth habit under photoperiod insensitive genetic background in dolichos bean (Lablab purpureus (L.) Sweet)

Development of high yielding cultivars with determinate growth habit in photoperiod insensitive (PIS) background is one of the major objectives of breeding grain legumes crops including dolichos bean. A thoroughly validated genetic basis is a prerequisite for breeding dolichos bean for determinate growth habit in PIS background. Based on the published reports by researchers of our laboratory and those by others, and our unpublished data, we hypothesized that the number and mode of action of genes controlling growth habit differ with degree of photoperiod sensitivity of the genetic material used to investigate the inheritance of growth habit in dolichos bean. To test this hypothesis, we compared the number and mode of action of genes controlling growth habit between segregating generations in Photoperiod sensitive (PS) and those in PIS genetic backgrounds. While indeterminate and determinate plants segregated in 15:1 ratio in F2 populations derived from crosses between determinate PIS and indeterminate PIS parents, they segregated in 9:7 ratio with indeterminacy being dominant in F2 populations derived from crosses between determinate PIS and indeterminate PS parents. These patterns of segregation (15:1 and 9:7) in favour of indeterminate and determinate plants, respectively in F2 populations were confirmed in F3 populations of PIS and PS genetic backgrounds based on good fit between observed and expected ratios (55:9 and 29:35, respectively) in favour of indeterminate and determinate plants, respectively. The patterns of segregation in F2 populations were further confirmed in F3 populations based on good fit between observed and expected ratios of 3:1 segregating and non-segregating families, and of 3:1 indeterminate and determinate non-segregating families, respectively.

Lethal and sublethal effects of bifenazate on the biological parameters of Tetranychus truncatus Ehara (Acari: Tetranychidae)

Tetranychus truncatus Ehara (Acari: Tetranychidae) is one of the serious pests that infests different agricultural crops in field and greenhouse crops, and its distribution is limited to mostly Asian countries. The experiments were conducted to know the effectiveness of different concentrations of bifenazate against the T. truncatus, and to evaluate and compare the demographic parameters of T. truncatus on host plant Lablab purpureus (L.) Sweet (Fabaceae), which were obtained from females treated with bifenazate. The LC15, LC30, LC50 and LC90 values are determined through the bioassay from the results of the first application of bifenazate on adult females of T. truncatus. The LC15, LC30, LC50 and LC90 concentrations of bifenazate were 0.417, 1.028, 2.591 and 24.792 ml/l, respectively. The response of adult females against the two lethal concentrations (LC15 and LC30) was mostly alike but had a little bit difference. The differences in life table parameters were observed between control and treated spider mites. The results demonstrated that LC15 and LC30 of bifenazate could reduce the survival rate, oviposition period, fecundity and longevity of females of T. truncatus and it significantly affected the developmental times, especially larval duration and fecundity of T. truncatus. Life-table parameters of T. truncatus were much reduced in LC15 and LC30 compared to the control and their growth and other factors showed significant differences. The present study showed that the lower lethal concentration (LC15 and LC30) of the tested acaricide showed negative effects on survivorship and life-table parameters of the subsequent generation of T. truncatus.