Ravish Choudhary

Socio-economic and horticultural potential of Khirni [Manilkara hexandra (Roxb.) Dubard]: a promising underutilized fruit species of India

Manilkara hexandra (Roxb.) Dubard (Khirni) is a socio-economically important fruit and nut species of tribal population of tropical deciduous forests of western and central India. Survey and collection missions were undertaken to study the extent of variability and socio-economic importance of Khirni germplasm in diversity rich areas of Rajasthan, Gujarat, Madhya Pradesh and Maharashtra. A total of 99 accessions of this important tree species were collected from surveyed regions, of which 47 diverse accessions were selected for morphological characterization showing wide range of variation in agro-morphological traits. During the survey, sizable variability in morphological characters and high socio-economic potential of Khirni was recorded. Bark, fresh fruits and extracted seeds have high nutritional and medicinal value. Tree provides substantial livelihood support to local inhabitants as collected fresh fruits from natural populations fetch good price in local markets. Besides livelihood support species, M. hexandra contributes in the nutritional security of the women and children of this area by fulfilling the need of micronutrients and vitamin A. Due to the high market demand of fresh fruits and seeds and without any organized cultivation, pressure on natural wild populations is severely building up since last several decades and therefore, the genetic variability of this species is now facing a great threat and need immediate complementary conservation efforts. Based on higher diversity index and natural population size of this species six in situ conservation sites have been suggested for dynamic conservation in western and central Indian states and 60 accessions have been successfully cryostored.

Inferring Phylogenetic Relationships of Indian Citron (Citrus medica L.) based on rbcL and matK Sequences of Chloroplast DNA

Phylogenetic relationships of Indian Citron (Citrus medica L.) with other important Citrus species have been inferred through sequence analyses of rbcL and matK gene region of chloroplast DNA. The study was based on 23 accessions of Citrus genotypes representing 15 taxa of Indian Citrus, collected from wild, semi-wild, and domesticated stocks. The phylogeny was inferred using the maximum parsimony (MP) and neighbor-joining (NJ) methods. Both MP and NJ trees separated all the 23 accessions of Citrus into five distinct clusters. The chloroplast DNA (cpDNA) analysis based on rbcL and matK sequence data carried out in Indian taxa of Citrus was useful in differentiating all the true species and species/varieties of probable hybrid origin in distinct clusters or groups. Sequence analysis based on rbcL and matK gene provided unambiguous identification and disposition of true species like C. maxima, C. medica, C. reticulata, and related hybrids/cultivars. The separation of C. maxima, C. medica, and C. reticulata in distinct clusters or sub-clusters supports their distinctiveness as the basic species of edible Citrus. However, the cpDNA sequence analysis of rbcL and matK gene could not find any clear cut differentiation between subgenera Citrus and Papeda as proposed in Swingle’s system of classification.

Genetic resources of Chironji (Buchanania lanzan Spreng.): a socio-economically important tree species of central Indian tribal population

Buchanania lanzan Spreng. (Chironji) is a socio-economically important underutilized fruit and life support species of tribal populations of north, west and central India. A survey and germplasm collection programme undertaken in the Indian states of Rajasthan, Gujarat and Madhya Pradesh observed that B. lanzan is found as natural wild in the forest, marginal lands and occasionally in farmer’s fields. A total of 72 diverse accessions of this important tree species were collected from the diversity–rich areas of India having wide range of variation in agro-morphological traits among the accessions. This species has high socio-economic value providing livelihood to tribal population of these areas and has high potential as commercial horticulture species. Fresh ripen fruits and extracted seed kernels have several nutritional and medicinal properties. Seed kernel and extracted kernel oil is used for the preparation of several Indian dishes. Traditional indigenous knowledge revealed immense importance of almost all parts of plant like roots, leaves, fruits, seeds and gum for various medicinal applications like cure for blood disorder, fever, ulcers, burning sensation of body, diarrhoea, dysentery, asthma, snakebite, etc. Due to direct harvesting of economically important parts of tree from natural habitat, genetic resources of B. lanzan are facing severe threat of extinction and need immediate conservation efforts.

Integrated Disease Management of Root Rot of Papaya in Eastern Gangetic Plains of India

The root rot disease is one of the major problems for papaya cultivation in eastern Gangetic plains of India. Field experiments for two years were conducted during 2013–14 and 2014–15 to evaluate the efficacy of cultural practices, agronomical practices along with chemical fungicides applied as soil drenching either individually or in combinations. The experiment was planned to work out the integrated disease management system against root rot disease in papaya, and simultaneously their role in enhancing the fruit yield and its attributes. The results indicated that organic mulch and soil mounding either singly or in combination reduce the disease incidences along with increase in papaya yield and its attributes. Application of organic mulch + soil mounding with fungicide drenching reveals their posi-tive combined effect on reduction of disease inci-dence and severity levels along with increase in fruit yield and its attributes. Integrated approach-es including organic mulch + soil mounding + soil drenching with metalaxyl + mancozeb re-vealed significantly the highest control of root rot disease (97%) along with the highest increase in fruit yield (36%) and its contributing traits. The highest disease incidence (45%) along with the lowest fruit yield/plant (33.28 kg) and its attrib-uting traits were recorded in control during both the years, 2013–14 and 2014–15. Organic mulch and soil mounding is most effective for disease management in the North Eastern Plains Zone (NEPZ), especially in sandy loam soils. Results of the present study elucidate the combined effect of integrated disease management practices (organic mulch + soil mounding and soil drench-ing with metalaxyl + mancozeb) for root rot man-agement in papaya under eastern Gangetic plains of India.

First report of Sclerotinia rot of pigeonpea caused by Sclerotinia sclerotiorum (Lib.) de Bary in India

Abstract Sclerotinia stem rot caused by Sclerotinia sclerotiorum (Lib.) de Bary was observed for the first time on pigeonpea in Pusa, Bihar (India) during the years 2012–2014. Typical symptoms of the disease included blighting of twigs, stem lesions, and development of cottony white mycelium and numerous large sclerotia on diseased plant parts. The fungus was identified on the basis of cultural and morphological characteristics, and its pathogenicity was also established. The internal transcribed spacer (ITS) region of pathogen was amplified with primers ITS1 and ITS4, which revealed 100% query coverage along with 99% identity with S. sclerotiorum recovered from different hosts. The highest disease incidence was recorded on cultivar ‘ICPL151’, whereas cultivars ‘MAL13’ and ‘Kudrat’ were observed to have significantly less disease under natural conditions.

New fruit and seed disorders in Papaya (Carica papaya L.) in India

Systematic field screening was conducted in 14 important papaya germplasm lines to observe the severity of bumpy fruit incidence. The disease severity, fruit yield and economic losses due to physiological disorders were observed. Pune Selection-3 was most sensitive (64.6%) for the disorder while Pusa Selection Red was most tolerant (4.2%). The maximum yield was obtained in Pune Selection-3 (62 kg/plant) while lowest yield in Mokama Local (20 kg/plant). The lowest market acceptability and highest economic loss were also observed in Pune Selection-3 (Rs. 3.3/kg and 11, 21,580/ha, respectively) due to highest incidence of bumpy fruit disorder as compared to other germplasm. The highest frequency of deformed seeds/fruit (83.6%) and economic loss (Rs. 84,400/ha) under fruit production for market was noticed during February, while the lowest deformed seeds/fruit (2.7%) were observed during December. The maximum incidence of vivipary and white seed disorders were observed during May (13.4 and 75.7%, respectively) while least incidence was observed in February and March (10 and 5%, respectively). The increased incidence of vivipary was observed in harvested fruits from February to May with increasing average monthly temperature. The low and high temperatures during seed maturation period aggravate deformed and vivipary seeds, respectively. Keywords: Carica papaya , physiological disorders, bumpy, vivipary, white seeds African Journal of Biotechnology, Vol. 13(4), pp. 574-580, 22 January, 2014