Enhancing nutrient translocation,yields and water productivity of wheat under rice–wheat cropping system through zinc nutrition and residual effect of green manuring

Abstract

Efficient nutrient and water use are two important considerations to obtain good harvests of wheat. This necessitates the development of an effective nutrient management technique that not only increases yield, but simultaneously can save nutrient and water use. In this context, a field experiment was conducted at Indian Agricultural Research Institute, New Delhi, India to evaluate the residual effect of sesbania and rice bean (in-situ), subabul (ex-situ) green manuring and Zinc (Zn) fertilization, using chelated Zn-ethylenediaminetetraacetic acid (Zn-EDTA) on nutrient use, yields and water productivity of wheat under rice–wheat cropping system. Among residual effects of green manure crops and Zn fertilization, sesbania and foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 days after sowing (DAS) recorded significantly higher nutrient content and uptake and yields than other green manure crops and Zn treatments. Residual effect of sesbania saved about 46.5?×?10³ and 30.5?×?10³ L irrigation water per tonne of wheat over subabul and rice bean, respectively. Foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 DAS saved about 55.5?×?10³, 47?×?10³ and 13?×?10³ L irrigation water per tonne wheat over residual effect of 5?kg Zn ha^?1 through chelated Zn-EDTA as soil application, 2.5?kg Zn ha^?1 through chelated Zn-EDTA as soil application + 1 foliar spray of 0.5% chelated Zn-EDTA at flowering and foliar spray of 0.5% chelated Zn-EDTA at active tillering?+?flowering?+?grain filling, respectively. Correlation analysis showed positive correlation between Zn uptake and grain yield.     

Heterosis in landrace-based topcross hybrids of pearl millet across arid environments

This study quantified the magnitude of heterosis in pearl millet (Pennisetum glaucum) topcross hybrids produced by crossing 16 diverse landraces and three high yielding open-pollinating varieties on two homozygous male-sterile lines. Hybrids and pollinators were grown in 12 year ×;location combinations in India that were grouped into three zones. Genetic components of variance quantifying the differences among these hybrids were estimated. The hybrids showed a conspicuous heterosis for grain yield, earliness and biomass yield but not for straw yield. The level and direction of heterosis for time to flowering depended strongly on the earliness of the male-sterile line. In the terminal drought stress zone hybrids made on the early maturing male-sterile line 843A had the highest level of heterosis for grain yield (88%). This was partly due to escape from terminal stress. In the other two zones the heterosis for grain yield was on average 30%. Heterosis for biomass yield and biomass yield per day was on average also positive in all three zones. For all traits, except time to flowering and biomass yield per day, pollinator effects were the only significant source of variation. Differences between hybrids were mostly caused by additive genetic effects. Significant amount of heterosis observed in landrace-based topcross hybrids for grain yield and other productivity-related traits suggested that substantial improvement in pearl millet productivity in and environments can be obtained by topcrossing locally adapted landraces on suitable male-sterile lines. This revised version was published online in July 2006 with corrections to the Cover Date.     

Performance of pearl millet isonuclear hybrids involving different cytoplasmic male-sterility systems

The performance of pearl millet hybrids involving four sources of cytoplasmic male sterility (CMS), including the most-exploited A₁ source, was compared to evaluate the effects of cytoplasm on grain yield. The mean grain yield of hybrids possessing A₂, A₃ and A₄ cytoplasms was either similar to or significantly higher than that of their counterpart hybrids with A₁ cytoplasm. Hybrids based on A₃ and A₄ cytoplasms produced, on average, 8% more grain compared with those based on A₁ cytoplasm. This suggested that these CMS sources could be used as alternatives to A₁ cytoplasm to widen the cytoplasmic base of hybrids. The results indicated that most of the variation in hybrids was accounted for by pollinator and cytoplasm × pollinator interactions, suggesting the use of genetically diverse pollinators in pearl millet hybrid breeding.     

Influence of cyto‐sterility sources of female line on seed quality of Indian mustard (Brassica juncea L. Czern & Coss.) in relation to storage period

Effect of cyto‐sterility sources on morphology and yield attributes in F₁ has well been studied in different crops, but not on the seed quality of hybrid. Six cytoplasmic male sterile (CMS) lines, viz. Ogura, Siifolia, Erucoides, Moricandia, Tournefortii and Oxyrrhina, which represent six different sources of CMS, were pollinated by a single maintainer line (‘Pusa Bold’) to check whether CMS sources have any marked effect on seed quality. Seeds were collected in 2007–2008 (rabi season: October–April) from CMS maintenance plot and kept in ambient storage for next 3 years. The results indicated that CMS/cyto‐sterility sources influenced the seed quality parameters in fresh seed as well as after storage. Per cent germination (as means over the storage period) was recorded up to 89.00, 88.25 and 87.88 in Moricandia, Ogura and Oxyrrhina systems, respectively, and it was significantly different from Tournefortii and ‘Pusa Bold’ (70.13 and 74.38, respectively). The CMS sources also had pronounced effect on other seed quality traits, viz. root and shoot length and seedling dry matter, and Ogura and Moricandia (green) performed better.     

Modelling surplus canal water releases for artificial recharge of groundwater through surface drainage systems

 Intensive agriculture in various countries has resulted in over-exploitation of groundwater resources leading to a decline in the water table. Artificial groundwater recharge offers a good method of preventing the water table from declining further. The Indo-Gangetic plain is currently facing the problem of a declining water table. The network of surface drains constructed to control previous waterlogging could now be used for recharging groundwater with surplus canal water during the low irrigation requirement period, as most of the drains cut across the irrigation canals. Therefore, a model was developed to determine the optimum discharge to be released at the head of each drain under natural flow conditions and with interruption in the flow by providing check structures across the drains at suitable intervals. In the proposed method, water is released in such a way that outflow becomes zero at the outfall of the drain. The results obtained reveal that the strategy developed could be adopted for recharging the declining water table through surface drainage systems. Received: 3 February 1999     

Water balance model for paddy fields under intermittent irrigation practices

A water balance model applicable to intermittent irrigation practice in rice fields was developed. The model inputs consist of climatic data and soil parameters. The model is formulated to simulate various processes such as evapotranspiration, deep percolation, surface runoff and depth of irrigation water to be applied on a daily as well as a seasonal basis. It also simulates daily ponding depth in the field. Both saturated and unsaturated water flow concepts were incorporated into the model to predict deep percolation loss during wet and dry periods of the field. The model was validated using data collected from field experiments. The details of model development and validation are outlined in this paper. Received: 21 December 1999     

White pine (Pinus strobus L.) regeneration dynamics at the species’ northern limit of continuous distribution

The abundance of eastern white pine (Pinus strobus L.) has been significantly reduced across its distribution range over the past few centuries. The species’ regeneration dynamics is well documented in the centre of its range, but is poorly understood at the northern limit of continuous distribution. To address this knowledge gap, we quantified natural white pine regeneration in unmanaged mature stands, identified the most important variables influencing it, and evaluated the impact of damaging agents, namely white pine blister rust (Cronartium ribicola J.C. Fisch.), white pine weevil (Pissodes strobi Peck), and herbivory. We also quantified the influence of remnant stands and residual trees on the spatial distribution of regeneration in logged sites. The results reveal continuous but low recruitment in mature stands. The basal area of balsam fir (Abies balsamea (L.) Miller) had a strong negative effect on white pine regeneration. Regeneration was more abundant than expected on moister substrates, including moss, decaying wood and organic matter. White pine regeneration was noted in recently logged areas, where distance from remnant stands had a significant effect on the abundance of white pine regeneration. The northern limit of continuous distribution holds potential for white pine restoration, for example by preserving remnant white pine stands that can provide seed sources for natural regeneration in a shelterwood cut system, or in adjacent clearcut areas. This study illustrates that different management strategies should be used near northern range limits, where effects of site conditions and disturbance agents are different than in the center of a species’ range.     

Adventitious rhizogenesis in Bambusa nutans and Bambusa tulda: Influence of seasonal variation, IBA and cutting type

The influence of seasonal variation, indole-3-butyric acid (IBA) and type of cuttings was examined on induction and growth of adventitious roots in Bambusa nutans Wall. and Bambusa tulda Roxb. Singlenode culm and culm-branch cuttings from the mature culms were provided with immersion treatment for 24 h of either water (control) or 2 mM IBA in four different seasons, i.e., spring (mid February), summer (mid May), rainy (mid July), and winter (mid November) and maintained for two months in the mist chamber at the relative humidity of (70±5)% and the temperature of (30±2)°C. In B. nutans, adventitious rooting occurred in both types of cuttings in all the seasons with the best rooting in the summer season i.e., May (88% in culm cuttings) and the least in winter. On the contrary, adventitious rooting was recorded only in culm cuttings in spring and summer season in B. tulda. IBA treatment significantly enhanced rooting, root number and root length; registering 14 to 17 times improvement over control in the best rooting season. Three factor-interactions (season × cutting type × IBA treatment) were significant for rooting in B. nutans and all characteristics, except sprouting in B. tulda. Thus, single-node culm and culm-branch cuttings in B. nutans and culm cuttings in B. tulda treated with 2 mM IBA during spring (February) to summer (May) season are recommended for their clonal multiplication.     

Cassia occidentalis L.: A review on its ethnobotany,phytochemical and pharmacological profile

Cassia occidentalis L. is an annual or perennial Ayurvedic plant which is used in several traditional medicines to cure various diseases. This weed has been known to possess antibacterial, antifungal, antidiabetic, anti-inflammatory, anticancerous, antimutagenic and hepatoprotective activity. A wide range of chemical compounds including achrosin, aloe-emodin, emodin, anthraquinones, anthrones, apigenin, aurantiobtusin, campesterol, cassiollin, chryso-obtusin, chrysophanic acid, chrysarobin, chrysophanol, chrysoeriol etc. have been isolated from this plant. The presented review summarizes the information concerning the botany, ethnopharmacologyquery, phytochemistry, biological activity and toxicity of the C.occidentalis plant.     

Influence of synthetic plant growth substances on the survivorship and developmental parameters of <Emphasis Type="Italic">Spilarctia obliqua</Emphasis> Walker (Lepidoptera: Arctiidae)

The nontarget effects of three plant growth stimulants (gibberellic acid, Siapton and triacontanol) and two plant growth retardants (chlormequat chloride and mepiquat chloride) on the survivorship and developmental parameters of Spilarctia obliqua Walker (Lepidoptera: Arctiidae) were studied. For each compound, various concentrations (0.125×, 0.25×, 0.5×, × , 2× and 4×; × = labeled dose) bracketing the labeled dose were prepared by serial dilution and mixed with an artificial diet for the insect. Gibberellic acid caused an increase in the larval period at × − 4×, but no marked difference was observed in the pupal period or in larval survival at any concentration. Siapton induced a significant increase in larval period at the two highest doses but caused significant reduction in pest survival at × − 4×. Interestingly, triacontanol induced a significant reduction in pest survivorship at almost all doses. The LC₅₀ for triacontanol was 0.206% and LT₅₀ was 266.5 hours at the labeled dose. However, triacontanol did not cause any significant difference in larval or pupal periods at any dose tested. Chlormequat chloride and mepiquat chloride caused significant reduction of larval survivorship at concentrations higher than the labeled doses, and no effect on the larval period. Intriguingly, a significant reduction in pupal period was observed with chlormequat chloride at × and 0.25×. Based on the marked effect of triacontanol on pest survivorship, this study suggests incorporating triacontanol in integrated pest management modules for S. obliqua. Caution in the use of gibberellic acid and Siapton for pest infestations is also indicated.