Diversity among melon (Cucumis melo L.) landraces from the Indo-Gangetic plains of India and their genetic relationship with USA melon cultivars

We report here the first broad genetic characterization of farmer-developed landraces of melon (Cucumis melo L.) from the Indo-Gangetic plains of India, an area overlooked in previous melon genetic diversity analyses of Indian melon germplasm. Eighty-eight landraces from three melon Groups in two subspecies (C. melo subsp. agrestis Momordica Group, and C. melo subsp. melo Cantalupensis Group and Reticulatus Group) were collected from the four agro-ecological regions (six sub-regions) of two northern states of the Indo-Gangetic plains of India, Uttar Pradesh and Uttarakhand. Significant differences were found among the landraces and eight USA Reticulatus Group reference cultivars for 18 plant and fruit traits: no. of primary branches per plant, days to marketable maturity, sex expression, fruit shape, flesh colour, netting, no. of fruit per plant, fruit weight, shelf life, total soluble solids (°Bx), ascorbic acid (mg/100 g), titratable acidity (%), fruit length and diameter, seed cavity length and diameter, flesh thickness, and resistance to Cucumber mosaic virus. The three melon groups differed significantly for 10 of the plant and fruit traits. Cantalupensis Group and Reticulatus Group accessions were andromonoecious, and the Momordica Group was monoecious. Neighbour-joining (NJ) tree and factorial correspondence analysis (FCA) of simple sequence repeat loci also revealed a high level of genetic variability in this germplasm. The 96 melon genotypes clustered into five groups in the NJ tree analysis: the 16 Indian Reticulatus Group accessions and eight USA reference cultivars formed a distinct group; and the 60 Cantalupensis Group accessions clustered in four other groups with the 12 Momordica Group accessions in a distinct subgroup of one of the Cantalupensis groups. The FCA plot largely confirmed the NJ tree with three distinct groups, one for each melon group. The close affinity of the Indian and USA Reticulatus melons was not unexpected, but it is not clear whether it was inherent in the group and maintained as Reticulatus melons moved from India through Central Asia and Europe to North America, or the result of recent intercrossing of Indian landraces with the USA-derived cultivars and selection for a broad range of Reticulatus type melons.     

Quantitative Estimation of Genetic Variability in Morphological Characteristics of Eastern Cottonwood (Populus deltoides Bartr.) Clones

The study was carried out to analyze the genetic variability for different growth parameters in poplar clones at the age of 2 and 3 yr in the nursery. Forty-nine exotic and indigenous clones of poplar were evaluated for eight morphological traits. Clones were planted in randomized block design (RBD) with three replications with four clones in a block in each treatment. Observations for different characters were recorded on six selected competitive clones per genotype. Results showed a high interclonal variability for most parameters. Statistically significant differences among clones indicated that the majority of study characters are controlled by genetic factors, specific to each clone. Highly significant genotypic difference supported by wide range of variation of mean and range values were observed for the characters under study. Significant and positive correlation was observed between diameter at breast height (DBH) and plant height. Leaf lamina length showed positive and significant correlation with petiole length, total leaf length, leaf width, and L/B ratio. Total leaf length showed positive and significant correlation with leaf width and L/B ratio. High estimates of heritability (in a broad sense) were observed for almost all characters in the study. High genetic advance expressed as percent of mean was recorded for petiole length (60.90), followed by plant height (60.78) and collar diameter (44.19) at 2 yr. At the age of 3 yr, genetic advance was found maximum for petiole length (60.05), followed by collar diameter (47.62) and plant height (45.29). The efforts for selecting new clones and their field-testing must continue under a long-term improvement plan so that the best clones can be recommended for plantations and hybridization programs.     

Effect of ammonia-N on growth and feeding of juvenile Macrobrachium rosenbergii (De-Man)

Survival rate, growth and feed intake were determined for late juveniles (4.31 ± 0.18 g) of river prawn Macrobrachium rosenbergii in freshwater with total ammonia‐N (NH₃‐N+NH₄‐N) concentrations of 0.015 (control), 0.5, 1.0 and 1.5 mg L⁻¹ for 60 days at pH 7.53 ± 0.04 and temperature 24.0 ± 2.5°C. Survival rate was significantly (P<0.05) lower (54 ± 4.2–70 ± 5.4%) for total ammonia concentrations from 0.5 to 1.5 mg L⁻¹ [0.0139–0.0419 mg L⁻¹ of unionized ammonia (NH₃)]. Growth (0.026–0.030 g day⁻¹ range) of the prawns did not differ for the different NH₃ levels but were significantly (P<0.05) lower compared with control (0.056 g day⁻¹). Feed intake rates also diminished significantly (P<0.05) from 77.60 ± 2.45% at control (0.015 mg L⁻¹ NH₃‐N) to 48.69 ± 2.13% at 1.5 mg L⁻¹ NH₃‐N (0.0419 mg L⁻¹ of unionized NH₃).     

Characterization and identification of leaf morphology of <Emphasis Type="Italic">Populus deltoides</Emphasis> Bartr. clones

Leaves are of fundamental importance to plants, representing their facility to generate power and are the sensing units of plants towards the environment. An attempt was made to characterize and compare the variations of leaf morphology of various Populus deltoides Bartr. clones by studying the winter buds and other leaf parameters of fully developed leaves. To achieve these objectives, forty-three exotic and indigenous clones of P. deltoides Bartr. were evaluated for different parameters. On the basis of various morphological characteristics the results reveal that each clone has a distinct color pattern of leaves. Different colors observed in these clones varied from light green through green to dark green. Two distinct lengths of the leaf apex were found, i.e., short and long; as well both acuminate and acute apex types were found. Erratic distribution of serration of leaves was also found. In this study, the morphological traits of leaves provided discriminatory grounds for separating various populations of P. deltoides Bartr. clones. Winter bud studies indicate that different clones vary considerably with regard to shape, color, shape of leaf scars and exudation.     

Potassium isotherm partitioning based on modified quantity‐intensity relation and potassium buffering characterization of soils of North India

Background : Potassium (K) availability in soil and plant uptake is restrained by the dynamic interactions among the different pools of K. Aims : To understand these interactions, a study was undertaken to assess the quantity–intensity (Q/I) and buffering characteristics of rainfed maize (Zea mays L.) growing soils. Ten contrasting soils were evaluated for K partitioning changes in exchangeable K (ΔEK) and non‐exchangeable K (ΔNEK) pools in the soil‐solution phase and buffering characteristics using a modified version of Q/I approach. Results : The partitioned Q/I isotherms showed strong adsorption with the increase in K concentration ratio (CR^K) and the changes due to ΔEK were higher than changes due to ΔNEK. Total buffering capacity (PBC^K) significantly correlated (r = 0.92, p <0.01) with clay content with a major share contributed by buffering capacity owing to non‐exchangeable K ( ${\mathrm{PBC}}_{\Delta \mathrm{NEK}}^K$) rather than exchangeable K ( ${\mathrm{PBC}}_{\Delta \mathrm{EK}}^K$). The fixation capacity (β) factor, the magnitude of added K converted into a non‐exchangeable pool, ranged from 41 to 63%, whereas release (α) factor, the magnitude of added K converted to the exchangeable pool, ranged from 19 to 36%. Both threshold solution K (CK_r) and threshold exchangeable K (EK_r) values were found to be high in Satran clay loam (S2) and lower in Doon silty clay loam (S3) soils. The equilibrium exchangeable K (EK_o) was found close to minimum exchangeable K (E_min) in Doon silty clay loam (S3) and Babaweyl sandy clay loam (S1) soils and overall E_min constituted about 8.94 to 0.57% of the EK_o. Conclusion : It may be concluded that K Q/I isotherm partitioning provides a valuable insight to assess the dynamic relations. The ratio of α/β (K recharge index) could be used to evaluate the K enrichment capacity of soil to K additions while EK_r and E_min can be potentially useful in the elucidation of exchangeable K as K fertility index especially in soils with poor K fertilizer management.     

Evaluation of the susceptibility of modern,wild, ancestral,and mutational wheat lines to Septoria tritici blotch disease

Globally, bread wheat production is threatened by fungal diseases, including the devastating disease Septoria tritici blotch (STB). Given the global importance of STB, and the difficulty in identifying novel sources of resistance to this disease, we screened a variety of wheat genotypes, including wild, ancestral, and mutagenized lines, for their STB response. This delineated a panel of wild wheat relatives and Watkins collection lines with exceptional resistance to a range of Zymoseptoria tritici isolates, some of which are highly virulent on modern, elite wheat varieties. Additionally, we characterized the STB susceptibility of 500 lines of the wheat cultivar Cadenza TILLING population and developed backcross derivatives of two TILLING lines that show dominant partial resistance to STB. These backcross lines are partially resistant to multiple isolates of Z. tritici, and, with the wild and ancestral lines identified, provide a useful reservoir of STB-resistant germplasm for use in wheat breeding programmes.     

Heavy Metal and Nutrient Ion Accumulation by Two Black Gram Cultivars Treated with Copper and Lead

ABSTRACT

A pot experiment was conducted to examine the uptake of nutrients (K⁺ (potassium) and Ca²⁺ (calsium)) and heavy metal (Cu²⁺ (copper) and Pb²⁺ (lead)) ions by leaves, seeds, and roots of two black gram [Vigna mungo (L.) Hepper] cultivars, ‘Mash-95018’(V₁) and ‘Mash-97’(V₂) treated with copper (Cu) and lead (Pb) at 25mg L^?1 and 50mg L^?1. This study was conducted in a greenhouse in the Botanical Garden, University of Agriculture, Faisalabad, Pakistan, during the spring of 2003. Heavy-metal treatments were applied 30 d after germination, and nutrient and heavy-metal ion uptake data were collected 10 d after treatment application. Both heavy metals in both cultivars substantially reduced nutrient ion accumulation and its translocation to seeds. Leaves had proportionately more K⁺ and Ca²⁺ than that recorded for roots and seeds after heavy-metal treatments. Nevertheless, both heavy metal (Cu²⁺ and Pb²⁺) ions ware predominantly sequestered in the roots, rather than in leaves and seeds, under their respective treatments. As the external concentrations of heavy metals increased, their uptake by the respective treated plants also increased, but nutrient ion (K⁺ and Ca²⁺) uptake was gradually reduced. This result suggests a concentration-dependent phenomenon. Overall, lead (Pb²⁺) showed more toxic effects on the uptake of essential nutrients compared with Ca²⁺, while ‘Mash-97’proved more sensitive to heavy metals than ‘Mash-95018.'     

Promoting Growth,Yield, and Phosphorus-Use Efficiency of Crops in Maize–Wheat Cropping System by Using Polymer-Coated Diammonium Phosphate

Field experiments were conducted at Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan, to check the effect of polymer-coated diammonium phosphate (DAP) on maize–wheat cropping system. Different rates of polymer-coated and uncoated phosphorus (P) were applied first to maize then followed by wheat after harvesting of maize on same field. Results showed that application of 100% of recommended P from polymer-coated DAP increased plant height (10%), chlorophyll content (4%), biological yield (17%), grain yield (36%), agronomic efficiency (43%), and nitrogen, phosphorus, and potassium contents of maize produces, while in case of wheat 75% recommended P from polymer-coated DAP increased plant height (6%), chlorophyll content (18%), biological yield (20%), grain yield (14%), agronomic efficiency (72%), and nitrogen, phosphorus, and potassium contents of grains and straw as compared with uncoated DAP. So, it can be summarized that polymer-coated DAP can effectively improve growth, yield, and phosphorus-use efficiency of maize and wheat crop.     

Estimation of secondary metabolites of indigenous medicinal plant extracts and their in vitro and in vivo efficacy against tomato early blight disease in Pakistan

Journal of Plant Diseases and Protection - Fifteen Pakistan’s indigenous medicinal plant extracts were investigated for various secondary metabolites and their potential against tomato early...     

Effect of Biochar on Immobilization of Cadmium and Soil Chemical Properties

A pot experiment was conducted at Institute of Biotechnology and Genetic Engineering (IBGE), University of Agriculture Peshawar, Pakistan. To conduct the experiment, eight kilograms of air-dried soil were taken in each pot and the amendment biochar was added and mixed properly at different levels like 0%, 1%, 2% and 4% (w/w), respectively. All pots were spiked with Cd solution at the concentration of 10?mg kg^?1. The treatments were arranged in completely randomized design (CRD). Fourteen days old nursery plants of rice Oryza sativa L. were transplanted into pots. Five rice plants were grown in each pot. After transplantation of rice plant, the nitrogenous and phosphatic fertilizers (Urea and DAP) were incorporated at the standard rate. Standing water condition was kept for rice grown in pots. Rice plants were harvested after 70 days germination. Soil samples were collected from each pot after plant harvesting. After soil analysis, the given data elaborated that the concentration of Cd in soil was stabilized by the amendment from 8.7?mg kg^?1 (0%) to 4.2?mg kg^?1 (4%). Among the other soil parameters the minimum soil pH (7.31), EC (0.151?dSm^?1), soil organic matter (0.63%), N (0.13%), P (4.72?mg kg^?1) and K (55.6?mg kg^?1) were noted at 0% biochar application, while maximum pH (8.23), EC (0.231?dSm^?1), soil organic matter (1.67%), N (0.25%), P (8.96?mg kg^?1) and K (93?mg kg^?1) were found in the pot treated with 4% biochar. Hence, it was concluded that Cd was significantly immobilized with 4% biochar application.