Responses of maize × teosinte derived backcross inbred lines (BILs) to maydis leaf blight (MLB) disease

Euphytica - Rice growth and productivity are greatly affected by cold stress, which is likely to become more of a hindrance for high and stable rice yields. To identify cold tolerance at the...     

Dietary Multispecies Probiotic Supplementation Enhances the Immunohematological Responses and Reduces Mortality by Aeromonas hydrophila in Labeo rohita Fingerlings

A study was conducted to determine the immunomodulatory effect of probiotic mixture on the nonspecific immune response and disease resistance of Labeo rohita. Fish were fed with six different test diets with or without probiotics, namely, T1 (basal feed [BF] without probiotics), T2 (BF + Bacillus subtilis [BS] + Lactococcus lactis [LL]), T3 (BF + LL + Saccharomyces cerevisiae [SC]), T4 (BF + BS + SC), T5 (BF + BS + LL + SC), and T6 (BF + heat‐killed bacteria of BS + LL + SC). During the prechallenge period, significantly higher (P < 0.01) nitroblue tetrazolium assay (NBT), red blood cells (RBC), hemoglobin (Hb), globulin, and albumin content were recorded in the probiotic‐supplemented diet group. Feeding all the three probiotics significantly decreased (P < 0.01) the serum aspartate aminotransferases (AST), alanine aminotransferases (ALT), acid phosphatase (ACP), and alkaline phosphatase (ALP) activity and increased the myeloperoxidase (MPO) and immunoglobulin M (IgM) value. Significant difference in the NBT, Hb, serum albumin, and MPO was noticed in both prechallenged and postchallenged fish. Lowest survivability was recorded in the nonprobiotic fed group, followed by the group fed with heat‐killed probiotics, whereas the highest survivability was noticed in the group fed with all the three probiotics in live form. Thus, a probiotic mixture diet constituting of three probiotics in viable form is found to be optimum to enhance the immunity and postinfection survivability in L. rohita fingerlings.     

Assessing genetic resistance to spot blotch, <Emphasis Type="Italic">Stagonospora nodorum</Emphasis> blotch and tan spot in wheat from Nepal

Fungal leaf spot diseases of wheat (Triticum aestivum L.) in Nepal cause significant yield reduction. Although field testing has identified a few partially resistant cultivars, most wheat grown in Nepal lacks adequate resistance to leaf spot diseases. During 2009–2010, 116 local and commercial spring wheat cultivars and advanced breeding lines were selected from multi-year field experiments in Nepal and evaluated for seedling resistance to three leaf spot diseases: spot blotch, Stagonospora nodorum blotch (SNB) and tan spot races 1 and 5 (two of the most prevalent races) in the growth chambers at North Dakota State University, Fargo, ND, USA. The wheat cultivars and lines were artificially inoculated with individual pathogens or races at the two-leaf stage and disease reactions were evaluated 6 to 10 days after inoculation (DAI). Results indicated that 30%, 31%, 19% and 10% of the tested wheat cultivars and lines were resistant to spot blotch, SNB, tan spot races 1 and 5, respectively. Six advanced breeding lines (SW89-5422, BL 2127 = DANIAL88/HLB30//NL297, BL 3033, FILIN/IRENA/5/CNDO/R143//ENTE/MEXI-2/3/AE. SQUA (TAUS)/4WEAVER, GAN/AE.SQUARROSA (236)//DOY1/AE.SQUARROSA(447)/3/MAIZ/4/INQALAB91, Mayoor//TK SN1081/Ae. Squarrosa (222)/3/FCT, were resistant to spot blotch, SNB and tan spot race 1. Similarly, two wheat cultivars Chirya 3 and Chirya 7 were resistant to spot blotch, and tan spot races 1 and 5. The resistant wheat lines identified in this study represent potentially useful and untapped sources of resistance to multiple leaf spot diseases and should be utilized in wheat breeding programs in Nepal in order to develop wheat cultivars with broad-spectrum resistance.     

Mode of inheritance of Alcobaca,a tomato fruit-ripening mutant

Summary Alcobaca, an abnormally ripening tomato mutant, was crossed with the normal cultivar Rutgers. Examination of F₁, F₂ and BC₁ populations indicated that a single recessive gene controls the mutant phenotype. No maternal effect was detected.     

Identification of pearl millet [Pennisetum glaucum (L.) R. Br.] lines tolerant to soil salinity

Crop tolerance to salinity is of high importance due to the extent and the constant increase in salt-affected areas in arid and semi-arid regions. Pearl millet (Pennistum glaucum), generally considered as fairly tolerant to salinity, could be an alternative crop option for salt affected areas. To explore the genotypic variability of vegetative-stage salinity tolerance, 100 pearl millet lines from ICRISAT breeding programs were first screened in a pot culture containing Alfisol with 250 mM NaCl solution as basal application. Subsequently, 31 lines including many parents of commercial hybrids, selected from the first trial were re-tested for confirmation of the initial salinity responses. Substantial variation for salinity tolerance was found on the basis of shoot biomass ratio (shoot biomass under salinity/ non-saline control) and 22 lines with a wide range of tolerance varying from highly tolerant to sensitive entries were identified. The performance of the genotypes was largely consistent across experiments. In a separate seed germination and seedling growth study, the seed germination was found to be adversely affected (more than 70% decrease) in more than half of the genotypes with 250 mM concentration of NaCl. The root growth ratio (root growth under salinity/control) as well as shoot growth ratio was measured at 6 DAS and this did not reflect the whole plant performance at 39 DAS. In general, the whole plant salinity tolerance was associated with reduced shoot N content, increased K⁺ and Na⁺ contents. The K⁺/Na⁺ and Ca⁺⁺/Na⁺ ratios were also positively related to the tolerance but not as closely as the Na⁺ content. Therefore, it is concluded that a large scope exists for improving salt tolerance in pearl millet and that shoot Na⁺ concentration could be considered as a potential non-destructive selection criterion for vegetative-stage screening. The usefulness of this criterion for salinity response with respect to grain and stover yield remains to be investigated.     

Effect of Manganese and Iron on Growth and Feeding of Juvenile Giant River Prawn, Macrobrachium rosenbergii (De-Man)

Abstract.— The effect of either manganese or iron on survival, growth, and feeding of giant river prawn, Macrobrachium rosenbergii (De-Man), juveniles was studied in two separate experiments. Survival rates of M. rosenbergii juveniles (4.58 ± 0.48 g) following 60-d exposure to 0.01 (control), 0.3, 0.6, and 1.2 mg/L of total manganese (Mn) were 100, 93.3 ± 3.4, 83.3 ± 4.3, and 83.3 ± 4.3%, respectively, while the same were 100, 83.3 ± 3.6, 73.3 ± 3.3, and 63.3 ± 4.7%, respectively, at the total iron levels of 0.02 (control), 0.32, 0.65, and 1.2 mg/L. Average daily growth of the prawn was significantly ( P  < 0.05) lower at 0.3 mg/L and higher levels of total manganese compared to control (0.01 mg/L). Average growth of the prawn exposed to 0.65 and 1.2 mg/L total iron was significantly lower ( P  < 0.05) than in control (0.02 mg/L iron) and 0.32 mg/L treatments after 60 d of exposure. Feed utilization was significantly ( P  < 0.05) reduced in M. rosenbergii juveniles exposed to 0.3 mg/L and higher levels of manganese. Feed utilization was significantly ( P  < 0.05) reduced in the prawns at all the iron treatments compared to control (0.02 mg/L iron). The accumulation of Fe and Mn was minimum in the muscle and maximum in the hepatopancreas of the prawns.     

Effect of different oil cake sources on growth, nutrient retention and digestibility, muscle nucleic acid content, gut enzyme activities and whole-body composition in silver barb, Puntius gonionotus fingerlings

Six iso‐nitrogenous (30% crude protein) and iso‐energetic (15 kJ g⁻¹) diets were prepared using different oil cake sources, viz. groundnut, soybean, sunflower, sesame, mustard and mixed oil cakes as major ingredients, and protein sources along with a minimum of 5% fish meal in each diet and were fed to silver barb Puntius gonionotus fingerlings (16.20±0.11 g) ad libitum four times a day close to an apparent satiation level for a period of 60 days to determine the effect of diets on growth, nutrient utilization, apparent digestibility coefficient (ADC) of the nutrients in the diets, gut enzyme activity, muscle nucleic acid content and whole‐body chemical composition of fish. Significantly higher (P<0.05) weight gain, specific growth rate, protein efficiency ratio, nutrient retention, ADC of nutrients in the diets, DNA:RNA ratio, protease and amylase activity with lower (P<0.05) feed:gain values were recorded in fish‐fed groundnut and soybean oil cake‐based diets than other diets tested. Among the dietary treatment groups, significantly higher (P<0.05) whole‐body protein, lipid and energy were also found in groundnut oil cake‐ and soybean oil cake‐based diets. The study suggests that the groundnut and soybean oil cake‐based diets, which led to significantly higher (P<0.05) growth and nutrient utilization than the other oil cake‐based diets in P. gonionotus fingerlings, may be used for pond culture of this species.     

Reducing Nitrogen Leaching from Agriculture: An Essential Step toward Protecting the Environment in High Rainfall Areas of Taiwan

ABSTRACT

Reducing nitrogen (N) leaching from croplands is important to protect environmental quality and improve recovery of applied N. To contribute to this broader goal of nutrient management, a simple pot experiment evaluated the potential differences among urea (250 kg N ha^?1), urea+compost (125 kg N ha^?1 from urea + 125 kg N from 8 Mg ha^?1 of compost), compost (250 kg N from 16 Mg ha^?1 of compost) and a zero control (Ctrl), in terms of their effects on apparent N recovery (ANR), mineral N (N_min) leaching and soil retention of applied N. Cabbage (Brassica oleraceae L.) and corn (Zea mays L.) were grown in rotation where compost application was not repeated in the 2nd year. N_min leaching was monitored by adding 83 mm and 62 mm of water fortnightly to cabbage and corn crops, respectively for a total of 28 times in a two-year period. Combined (urea+compost) and independent (compost) treatment application retained 1.5 to 2 times higher N, and lowered 2.1 to 4.6 times N_min leaching, relative to independent (urea) application. We conclude that farmers’ practice of fertilization that has an inherent problem of N leaching for high rainfall areas in Taiwan could be improved by proper compost and urea combinations within agronomically recommended rates of N application.     

The genetic control of highly restricted branching in narrow-leafed lupin (Lupinus angustifolius L.)

Most current cultivars of narrow-leafed lupin have an indeterminate growth habit such that vegetative growth continues while the pods are being filled, causing strong intra-plant competition for assimilates. Restricted-branching (RB) genotypes can reduce this tendency and raise the proportion of the plant's biomass going into grain. Studies on the inheritance of the RB trait showed that two spontaneous mutants, P25598 and P21227, each carried a single incompletely dominant allele conferring the trait, whereas two other spontaneous mutants, P24743 and P25582, and two induced mutants, P26021 and P21238, each carried a single recessive allele conferring the trait. The RB alleles present in P26021 and P21238 seem to be the same, and to be at the same locus as (or tightly linked to) the allele controlling the RB trait in P21227. Similarly, the genes present in P21227 and the induced mutant P25735 appear to be the same when these lines are crossed. However, they do not behave the same in crosses with P26021: thus we propose that there are at least three alleles at the same locus (or at tightly linked loci) that confer RB. Normal-branching plants that are heterozygous at an RB locus generally have fewer leaves on the uppermost branch than homozygous-normal plants. Similarly, RB plants that are heterozygous generally have fewer branchless nodes on the main stem than homozygous-RB plants. The RB trait is associated with a small but significant reduction in the number of leaves on the main stem. However, this relationship is weak and will not prevent plant breeders from selecting both early- and late-flowering RB genotypes. This revised version was published online in July 2006 with corrections to the Cover Date.