Diversity Analysis in Horse Gram [Macrotyloma uniflorum (Lam.) Verdc.] Mutants

Background: Horse gram is the potential rainfed legume in Indian farming. The major limitation in horse gram breeding is the narrow variability. Variability induction and its estimation would sustain food security. Methods: Variability was induced using gamma rays, electron beam and ethyl methanesulfonate and their combinations. The induced variation for the economic traits, their inheritance and genetic gain were ascertained. Result: The analysis of variance indicated the induction of significant variation for yield attributing traits. The population was grouped into 10 constellations by the virtue of induced variation. The groups I, II and V were the largest comprising of 38, 31 and 19 mutants respectively. The mutants exhibited significant intra and inter group variation. The mutagens induced the maximum variability for plant height (32.24%), 100 seed weight (25.42%) and number of pods per plant (19.18%). The mutants possessed high genotypic and phenotypic coefficients of variation for all the characters except flowering traits and duration. The induced variability for the yield attributing traits possessed significant breeding value as the heritability (86.66%-99.72%) and genetic advance as percent of mean (10.65-81.94) were high and the environmental influence was the minimum.

Gamma rays induced morphological, flowering and palynological modifications in horse gram (Macrotyloma uniflorum)

Aim: The quest was framed to analyse the effect of high dose of gamma rays on morphological, flowering, and palynological traits in horse gram (Macrotyloma uniflorum). Methodology: Two horse gram varieties PAIYUR 2 and CRIDA 1-18 R were mutated using 32 mutagenic combinations. Sterile plants produced by gamma rays: 400 Gy were utilized to study the alterations in morphological, flowering characters in 20 randomly selected plants, and palynological traits using scanning electron microscope. Results: Gamma rays (GR):400 Gy produced sterile plants with altered ideotype and reproductive traits. It reduced expression of yield attributing traits, delayed first flowering, modified anther, and pollen size. The palynological changes included genotype dependant variation in pili number, size and exine ornamentation. Interpretation: High gamma ray dose is lethal to horse gram which was evidenced through grave modifications in morphological and palynological traits. These alterations resulted in sterility. Sterile plants tried to repair the irradiation induced damages and hence failed to perform routine reproductive functions.

How does the yield variability in rainfed crops respond to climate variables? Evidence from pulses yields in Telangana, India

PurposeThis paper aims to evaluate the effects of climate variables on the mean yield and yield variability of major pulse crops in the Telangana state of India.Design/methodology/approachAuthors have estimated the Just and Pope (1978, 1979) production function using panel data at the district level of four major pulses in nine former districts of Telangana for 36 years during 1980–2015. A three-stage feasible generalized least squares estimation procedure has been followed. The mean yield and yield variance functions have been estimated individually for each of these study crops, namely, Bengal gram, green gram, red gram and horse gram.FindingsResults have shown that changes in climatic factors such as rainfall and temperature have significant influences on the mean yield levels and yield variance of pulses. The maximum temperature is observed to have a significant adverse impact on the mean yield of a majority of pulses, and it is also a risk-enhancing factor for a majority of pulses except horse gram. However, the minimum temperature is positively related to the mean yields of the study crops except for Bengal gram, and it is having a risk-reducing impact for a majority of study crops. Rainfall is observed to have a negative impact on the mean yields of all pulses, but it is a risk-enhancing factor for only one crop, i.e. Bengal gram. Thus, rising temperatures and excess rainfall are not favorable to the productivity of pulses in study districts.Research limitations/implicationsThe present study is based on the secondary data at the district level and is considering only one state. Season-wise primary data, including farm-specific characteristics, could have been better. The projected climate change and its impact on the mean yields and yield variance of pulses need to be considered in a future study.Originality/valueAccording to the best of our knowledge, this is the first study to empirically evaluate the impact of climatic variables on the mean yields and yield variability of major pulses in Telangana using a panel data for major pulses and nine districts of 36 years time-series during 1980–2015. The study has given useful policy recommendations.

Pattern of Seed Development and Maturation in Horse Gram (Macrotyloma uniflorum Lam.)

Background: Seed maturation is genetically controlled process involves a series of morphological and physiological changes extending from fertilization to independence from the mother plant. Horse gram (Macrotyloma uniflorum Lam.) is an under exploited legume and it is an inexpensive source of protein, rich in minerals and vitamins. However, information on harvesting time of horse gram seeds are still limited. Therefore, this study was carried out in horse gram to determine the physiological maturity in obtaining good quality of seeds for better planting value.Methods: The laboratory experiment was carried out at Department of Seed Science and Technology, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai, India to determine the appropriate time of harvesting horse gram var. Paiyur 2 seeds. The crop was raised as bulk in the field during rabi season of 2019 and the pods were harvested in interval of seven days from 7 days after anthesis (DAA) to 56 DAA and subjected for determinations of pod and seed characteristics.Result: The result revealed that, pod length and pod fresh weight of seeds showed a steady increase upto 35 DAA showed maximum pod length (4.76 cm) and fresh weight of pods (6.903 g/10 pods). The seeds attained maximum germination (94%), dry weight (0.859 g/25 seeds) and vigour parameters viz., root length (17.7 cm), shoot length (8.8 cm), dry matter production (0.161 g/10 seedlings), vigour index I (2491) and vigour index II (15) on 49 DAA.

Generation of Micro-mutants for Yield and Component Traits in Horse Gram [Macrotyloma uniflorum (Lam.) Verdc.]

Background: Induced mutagenesis was employed in horse gram cv. CRIDA 1-18R with an objective of evolving mutants with increased yield potential. Methods: Based on preliminary study, the variety has been irradiated with desirable doses of gamma rays (200 Gy and 300 Gy), electron beam (100 Gy and 200 Gy) and its combination (100 Gy) and the material were forwarded to M2 generation following parent-progeny row basis. The genotypes exhibiting superior yield than control were further forwarded to M3 generation. Multivariate analyses were performed to determine the induction of micro-mutants for 11 quantitative traits.Result: The reduction in mean value over control was observed for most of the yield component traits at M2 generation. Among the mutagenic treatments, combination of gamma rays with electron beam registered high mean values for pod length (5.05 cm), number of pods per plant (54.42) and single plant yield (25.68 g) at M3 generation. Non-significant skewness and / or kurtosis at M3 population denoted the absence of epistatic interactions for plant yield. An increase in variability pattern, H2 and GAM at M3 generation indicated the scope for trait (plant height, number of seeds per pod, number of clusters per plant, number of pods per plant, biological yield and single plant yield) improvement through selection.

Studies on an Alternative Method for Preparation and Fermentation of idlis Made from Proso Millet (Panicum miliaceum L.), Horsegram (Macrotyloma uniflorum (Lam) Verdc.) and Fenugreek (Trigonella foenum-graecum L.)

The present study was undertaken to develop an alternative idli from proso millet with horse gram and fenugreek seeds. Two types of wet batters (Batter A & Batter B) were prepared by soaking the ingredients proso millet, horse gram and fenugreek separately (in the ratio by weight 7:2:1) in excess water for 8 hours at room temperature (25±2ºC). In method A, the ingredients were soaked in excess water and whereas in method B, fenugreek was soaked in buttermilk. The soaked ingredients were ground separately with adequate amount of water using a grinder and mixed with the addition of 1% salt. The resulting batter was fermented for 10 hours at room temperature. The batter was analyzed for its microbial load (Total Plate Count, Lactobacillus and Yeast and Mold) and physico-chemical properties (height rise, pH and titratable acidity) by drawing aliquots at fixed intervals. Microbial analysis revealed maximum load at 6th hour of fermentation for TPC, LAB and Yeast growth. Suppressing activity of the organisms was seen after this stage and there was a sharp decline in microbial growth (LAB and Yeast). The pH and total titratable acidity ranged between 4.88-6.20 and 0.19–0.51% respectively. The nutritional analysis and sensorial acceptance of the idli formulated with both the batters were also studied. Both the idlis were found to have a two-fold increase in protein content and a 50% reduction in carbohydrate content when compared with the traditional rice idli. The sensory analysis was conducted with 100 untrained panelists and the results revealed that idli prepared from Batter A was preferred. A dry ready to cook idli mix was also formulated and was studied for the above said properties. The study highlights that proso millet, horse gram and fenugreek can be used as an effective alternative for preparation of idli.

Genetics of growth habit in horse gram (Macrotyloma uniflorum (Lam.)Verdc.)

Growth habit is a plant architectural trait in grain legumes with no exception of horse gram. Determinacy and indeterminacy are the two types of growth habits reported in horse gram. Relative advantages of the two types of growth habit depend on the production systems to which cultivars are targeted. Dependable information on genetics of growth habit provide clues for adopting the most appropriate selection strategy to breed high yielding horse gram varieties with desired growth habit. Taking cues from the past studies, we hypothesize that growth habit in horse gram is controlled by two genes displaying inhibitory epistasis and indeterminacy is dominant over determinacy. To test this hypothesis, we monitored the inheritance of growth habit in F1, F2 and F3 generations derived from two crosses involving parents differing for growth habit. Contrary to our hypothesis, determinate growth habit of F1s of both the crosses suggested dominance of determinacy over indeterminacy. A good fit of observed segregation of F2 plants to that of the hypothesized segregation in the ratio of 13 determinate: 3 indeterminate plants, besides confirming dominance of determinacy, suggested classical digenic inhibitory epistatic control of growth habit. These results were further confirmed in F3 generation based on goodness of fit between observed numbers of plants segregating for determinacy and indeterminacy and those expected in the ratio of 49 determinate: 15 indeterminate plants. To the best of our knowledge, this is the first report on the inheritance of growth habit in horse gram.

Identification of Source of Resistance to Horse Gram Yellow Mosaic Disease (HgYMD) in French Bean (Phaseolus vulgaris L.)

Background: Horse gram yellow mosaic disease (HgYMD) is one of the major limiting factor for legumes production in India as it can cause economic loss up to 100%. Till date, horse gram yellow mosaic virus was rare to infect french bean, but now-a-days, it has become the major causal agent for yellow mosaic epidemics in the southern part of India. Few bush type varieties, resistant to yellow mosaic disease are released but not specifically resistant to HgYMD. So, systemic breeding work has been initiated to identify the resistant source for HgYMD in french bean. Methods: Seventyone genotypes of french bean were screened in a randomized complete block design (RCBD) with three replications under natural epiphytotic as well as artificial condition during Summer, 2018 at ICAR-IIHR, Bengaluru, India. Result: The genotypes varied for percent disease index (PDI), area under disease progress curve (AUDPC) and the apparent rate of infection per unit time period (r). Two varieties i.e., Jade-5058 and Arka Arjun were showing less PDI of 13.33 and 14.44, least average rate of infection of 0.64 and 0.65 and lowest AUDPC value of 350.54 and 359.16 respectively, compared to other genotypes. Average PDI of Arka Arjun and Jade-5058 were 13.33 and 12.22 under artificial screening, which were much lesser than susceptible check Arka Komal (PDI 92.22) and Arka Anoop (PDI 90.00). Resistant genotypes identified from this experiment can be used for breeding HgYMD resistant french bean lines.