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1.
A. A.?WamanEmail author Pooja?Bohra B. N.?Sathyanarayana K.?Umesha G. K.?Mukunda T. H.?Ashok Balakrishna?Gowda 《Erwerbs-Obstbau》2015,57(3):153-164
Factors concerning aseptic culture establishment and hardening were studied in detail in choicest Silk Banana. Effect of size of sucker (small, medium and large), carbon concentration (10, 20 and 30 g/l), season of initiation (wet and dry) and pre-treatments such as segmentation and incision to the explants were studied during initiation. Further, hardening related factors such as substrates used for primary and secondary hardening, nursery nutrition (source and frequency of application) and pre-treatments for ex vitro rooting were also studied. Results revealed that small suckers were most suited for initiations with the least contamination, maximum establishment and higher percentage of greening. Lower concentration of sucrose, though delayed greening, resulted in 100?% establishment of explants. Initiations performed during the drier period were completely free from the fungal contamination and showed less bacterial contamination than those performed during the rainy season. Segmentation of explant into four parts during first subculture supported maximum shoot proliferation by overcoming apical dominance. Coir pith was observed to be the most congenial substrate during primary hardening, whereas coir pith alone or sand: red earth: coir pith (1:1:1) supported superior performance of plantlets during secondary hardening. Single application of mono ammonium phosphate improved growth of plantlets during secondary hardening. Pre-treatment with mono ammonium phosphate gave the best response in terms of rooting and hardening of un-rooted micro-shoots. Thus, the discussed methodology could help the industries to take up commercial scale propagation of Silk Banana. 相似文献
2.
Drought is a major abiotic constraint for rice production worldwide. The quantitative trait loci (QTLs) for drought tolerance traits identified in earlier studies have large confidence intervals due to low density linkage maps. Further, these studies largely focused on the above ground traits. Therefore, this study aims to identify QTLs for root and shoot traits at the vegetative growth stage using a genotyping by sequencing (GBS) based saturated SNP linkage map. A recombinant inbred line (RIL) population from a cross between Cocodrie and N-22 was evaluated for eight morphological traits under drought stress. Drought was imposed to plants grown in 75 cm long plastic pots at the vegetative growth stage. Using a saturated SNP linkage map, 14 additive QTLs were identified for root length, shoot length, fresh root mass, fresh shoot mass, number of tillers, dry root mass, dry shoot mass, and root-shoot ratio. Majority of the drought responsive QTLs were located on chromosome 1. The expression of QTLs varied under stress and irrigated condition. Shoot length QTLs qSL1.38 and qSL1.11 were congruent to dry shoot mass QTL qDSM1.38 and dry root mass QTL qDRM1.11, respectively. Analysis of genes present within QTL confidence intervals revealed many potential candidate genes such as laccase, Calvin cycle protein, serine threonine protein kinase, heat shock protein, and WRKY protein. Another important gene, Brevis radix, present in the root length QTL region, was known to modulate root growth through cell proliferation and elongation. The candidate genes and the QTL information will be helpful for marker-assisted pyramiding to improve drought tolerance in rice. 相似文献
3.
Surya P. Bhattarai Robert C. de la Pena David J. Midmore Kadirvel Palchamy 《Euphytica》2009,167(1):23-30
The importance of fast-trackt generation advancement in developing superior germplasm has been recognized in breeding of many
crop species. To address this issue in tomato, immature seeds were excised from fruit at different maturity stages and transferred
to culture medium. The best culture medium was modified full strength Moorashige–Skoog (MS) salts supplemented with 0.1 mg l−1 IAA, 0.5 mg l−1 IBA, 0.5 mg l−1 GA3 and 2% sucrose. If the excised seeds were able to grow, most showed shoot formation after a week. Seeds extracted as early
as 10 days after pollination were successfully cultured provided they were transferred aseptically and without injury. No
morphological or physiological changes in regenerated plants and their fruit relative to the parent were detected. Germination
from immature seeds of tomato is a simpler alternative to in vitro culture of immature embryos or callus, as it can be undertaken
in comparatively less stringent laboratory conditions. Using this approach, five generations can be produced in a year in
contrast to a maximum of three generations with conventional methods. This offers an opportunity for rapid generation advancement
aimed towards population development when coupled with marker assisted selection in tomato breeding for biotic and abiotic
stress tolerance. 相似文献
4.
Paul C. Davidson Theresa B. Kuhlenschmidt Rabin Bhattarai Prasanta K. Kalita Mark S. Kuhlenschmidt 《Water, air, and soil pollution》2014,225(3):1-12
Overland transport kinetics of pathogens is controlled, in large part, by soil and vegetation. With an increasing number of concentrated animal operations, there is becoming a greater need to dispose of a vast amount of manure in a single, localized area. Animal manure contains a substantial amount of microbial pathogens, including Cryptosporidium parvum that may pose a threat of contamination of water resources. This study examines the kinetics of C. parvum in overland transport and critical factors involved in the design of best management practices, especially vegetative filter strips, to prevent the transport of harmful pathogens to water bodies. Three soil types were tested (Catlin silt-loam, Alvin fine sandy-loam, Darwin silty-clay), spanning the entire spectrum of typical Illinois soils. A 20-min rainfall event was produced using a small-scale (1.07 m?×?0.66 m) laboratory rainfall simulator over a soil box measuring 0.67 m?×?0.33 m. Each soil type was tested for pathogen transport kinetics with bare surface conditions as well as with smooth brome and fescue vegetative covers. Surface runoff, soil cores, and near-surface runoff were each analyzed for infective C. parvum oocysts using cell culture infectivity assays. Results showed that vegetation greatly reduced the recovery of infective oocysts, in addition to delaying the time to the peak recovery. However, there was no clear evidence of any one vegetation type being advantageous over another. The bare soil experiments resulted in a higher recovery of C. parvum oocysts from the Darwin soil compared to other two soils. Analyses of soil cores show a slightly higher recovery of oocysts in the Catlin soil compared to Alvin or Darwin soils. 相似文献
5.
Most trickle irrigation in the world is surface drip yet subsurface drip irrigation (SDI) can substantially improve irrigation
water use efficiency (IWUE) by minimizing evaporative loss and maximizing capture of in-season rainfall by the soil profile.
However, SDI emitters are placed at depths, and in many soil types sustained wetting fronts are created that lead to hypoxia
of the rhizosphere, which is detrimental to effective plant functioning. Oxygation (aerated irrigation water) can ameliorate
hypoxia of SDI crops and realize the full benefit of SDI systems. Oxygation effects on yield, WUE and rooting patterns of
soybean, chickpeas, and pumpkin in glasshouse and field trials with SDI at different emitter depths (5, 15, 25, and 35 cm)
were evaluated. The effect of oxygation was prominent with increasing emitter depths due to the alleviation of hypoxia. The
effect of oxygation on yield in the shallow-rooted crop vegetable soybean was greatest (+43%), and moderate on medium (chickpea
+11%) and deep-rooted crops (pumpkin +15%). Oxygation invariably increased season-long WUE (WUEsl) for fruit and biomass yield and instantaneous leaf transpiration rate. In general, the beneficial effects of oxygation at
greater SDI depth on a heavy clay soil were mediated through greater root activity, as observed by general increase in root
weight, root length density, and soil respiration in the trialed species. Our data show increased moisture content at depth
with a lower soil oxygen concentration causing hypoxia. Oxygation offsets to a degree the negative effect of deep emitter
placement on yield and WUE of SDI crops. 相似文献
6.
Root aeration improves yield and water use efficiency of tomato in heavy clay and saline soils 总被引：1，自引：0，他引：1
Water logging and salinity of the soil alter both the physical and biological environment of plant roots. In two experiments, we investigated the effects of imposed aeration on yield and the physiological response of tomato (Lycopersicon esculentum L.) variety Improved Apollo growing under protected conditions over a range of salinities (the salinity experiment), and under constant field capacity (FC) or drier soil conditions (the moisture experiment). Subsurface irrigation with aerated water (12% air in water) stimulated above-ground growth, and enhanced the reproductive performance through earliness for flowering and fruiting compared with the control. Fruit yield of tomato with aeration in the moisture experiment was increased by 21% compared with the control (4.2 kg versus 3.7 kg per plant), and the effect of aeration on fruit yield was greater in FC than in the drier treatment. Fruit yield was increased by 38% in saline soil due to aeration compared with the non-aerated control. Increasing salinity from 2 to 8.8 dS m−1, and 10 dS m−1 reduced fruit yield by 18% and 62%, respectively, but 4 dS m−1 did not suppress yield. Aeration in both the experiments increased plant water use and water use efficiency (WUE), expressed as weight per unit of applied water. Biomass WUE was greater by 16% and 32% in the moisture and salinity experiments, respectively. The increased yield with aeration was also accompanied by an increased harvest index (HI) defined as the proportion of dry fruit biomass to total dry biomass, greater mean fruit weight, high fruit DM, and increase in leaf chlorophyll content and shoot: root ratio, and a reduced water stress index (computed from the difference between air and leaf temperature). The benefit gained from aerating irrigation water was not only observed under conditions where air-filled porosity may be low (e.g., in poorly structure sodic soils, or at field capacity in clay soils), but also in drier soils. 相似文献
7.
The Azospirillum 10SW used in our experiments was isolated from roots of wheat growing in nitrogen-poor soil of a hilly region of Nepal, where
inorganic nitrogen fertilizers were never used. The main objectives of this work were to assess the effects of inorganic nitrogen
fertilization in the yield responses of wheat grown in association with the bacteria. The in vitro experiments were done in
laboratory, whereas the pot experiments were performed in a greenhouse. The nitrogenase activities of in vitro grown Azospirillum were repressed by nitrate. The magnitude of repression was lower when the bacteria were growing in association with wheat.
The number of roots per plant was increased significantly in inoculated plants irrespective of the nitrate concentration of
the medium. Inoculation with Azospirillum 10SW also increased the yield of wheat grown in pots with medium levels of nitrogen fertilization. These data show the possibility
of inoculation of this Azospirillum spp. in combination with nitrogen fertilizer to improve the yield of wheat. Azospirillum inoculation enhanced the development of roots and shoots in the early growth stages of wheat. It may be one of the factors
responsible for the yield increases.
Received: 11 December 1996 相似文献
8.
Wazir S Lakra Nachimuthu Sivakumar Mukunda Goswami & Ramesh R Bhonde 《Aquaculture Research》2006,37(1):18-24
Two new cell culture systems namely epitheloid cells of Lates (LCE) and fibroblastic cells of Lates (LCF) have been developed from fry and fingerling of the economically important brackishwater fish Lates calcarifer. Primary cultures were initiated by explant technique using caudal fin of fingerling and whole body tissue of the fry. The nutritional requirements and the growth pattern in response to different culture environment were similar for the two cell cultures. The culture medium used was Leibovitz‐15 supplemented with 20% fetal bovine serum (FBS) and 1% fish serum. The LCE comprised of epithelioid cells and LCF cells were fibroblastic. With a split ratio of 1:2, the confluency of cells was attained in 8–10 days at an incubation temperature of 28°C. The cells were found to grow well in a wide range of temperature (24–32°C) and stable at 20 and 36°C. The growth rate of LCF and LCE cells increased proportionately with the concentration of FBS from 5% to 20%. A decrease of serum level to 10% after eight subcultures produced no apparent change in cell morphology and growth rate. The viability of cells was found to be 70% when revived after a month of storage in liquid nitrogen (?196°C). 相似文献
9.
Results are reported from on-farm surveys of N2 fixation in Nepal, conducted between 1994 and 1999, involving the summer legumes soybean, mashbean and groundnut, and the winter legumes lentil and chickpea, at various locations in the Hill and Terai regions of Nepal. Additional less-detailed data were also collected for pigeonpea, grasspea and fababean. There were a total of 107 crops in the major and minor surveys. Estimates of the proportion of legume nitrogen (N) derived from N2 fixation (Pfix) were determined using the natural 15N abundance method. Mean estimates of Pfix for the various species were 62% (soybean), 47% (mashbean), 57% (groundnut), 78% (lentil), 79% (chickpea), 75% (pigeonpea), 87% (grasspea) and 85% (fababean). Estimates of total N fixed (including roots) were 59 kg N ha−1 (soybean), 28 kg N ha−1 (mashbean), 153 kg N ha−1 (groundnut), 72 kg N ha−1 (lentil), 84 kg N ha−1 (chickpea), 412 N ha−1 (pigeonpea) and 80 N ha−1 (grasspea and fababean). The on-farm measurements of N2 fixation were generally similar to those of experimental crops in the same areas of the country. Correlation matrices of soil fertility parameters, shoot dry matter and N, and N2 fixation revealed that the total amounts of N fixed were influenced primarily by crop growth. Based on the above figures, it was estimated that approximately 30,000 t N were fixed annually in Nepal by legumes, valued at US$ 15 million. 相似文献
10.
Hongjun Lei Surya Bhattarai Ron Balsys David J. Midmore Thomas Holmes William Zimmerman 《Irrigation Science》2016,34(6):421-430
The wider scale use of aerated water for irrigation has been limited by dis-uniformity of aeration in the field, limited longevity of oxygen in irrigation water and lack of knowledge of what oxygen concentration brings optimal growth. Two options are presented for increasing dissolved oxygen (DO) in irrigation water: Venturi (VT) and fluidic oscillator (FO) aeration systems. Sweet corn was grown in pots to evaluate the effect of aerated water. Compared to the control treatment (CK), VT and FO showed an increase in irrigated water DO in the irrigation tank and feeding pots after aeration. Incorporation of surfactant in the irrigation water significantly improved DO level for the VT and FO treatment. Typically the DO levels reached a peak when the pump is turned off and then decline to a minimum after 24 h. The VT and FO systems had a higher magnitude and duration of the DO level in the water in all treatments compared to the CK system. The FO aeration maintained the longest duration of elevated DO in the water by a factor of two compared to the VT aeration. Compared to the CK, the best result on longevity and DO concentration was achieved using 4 ppm of a non-ionic surfactant. The corn biomass was significantly greater for the VT compared to both the FO and CK treatments. 相似文献