Nowadays, various areas in the world have faced waterlogging and salinity problems, which are intensified by a myriad of factors including use of wastewaters for irrigation, unsuitable cropping pattern, torrential rains and floods, lack of sufficient drainage, uncontrolled drainage, lack of adequate knowledge, wrong management decisions, very poor construction and rehabilitation rates of drainage systems, increase of irrigation systems without paying any attention to their adverse impacts on soil and quality of water resources, etc One effective way to reduce waterlogging and salinity problems is drainage It is necessary to do a comprehensive study on previous works to arouse awareness of drainage, waterlogging, and salinity and to avoid trial and error policies in these fields The present paper aims to study drainage, waterlogging, and salinity in the different regions of the world and to present challenges and prospects for further research and making a better decision in this field The results indi

Drainage, waterlogging, and salinity

Groundwater resources management through the applications of simulation modeling: A review

This review paper presents the history of rust resistance breeding and deployment of resistant cultivars in different geographical areas of India. Much has been accomplished in controlling the wheat rusts through deploying resistant cultivars carrying diverse resistance genes in India. The genetic diversification in wheat has not only proved critical in developing resistant cultivars but also in the understanding of disease epidemiology and its dynamics and has gradually reduced the magnitude and frequency of epidemics. The gene Lr26 in combination with Lr13, Lr23 and Lr34 and the Agropyron segment carrying Lr24/Sr24 have played a crucial role in providing durable resistnace and protecting wheat from any epidemic threat to stable wheat production. In recent years, wheat has achieved relatively higher production stability as compared to other cereal crops by adopting strategic gene deployment. Only marginal increase in wheat area is recorded but the strategic deployment of rust resistance genes is most protective of crop production and crucial in sustaining the production levels.

Wheat rusts in India: resistance breeding and gene deployment - a review.

Water and salt balance studies, using SaltMod, to improve subsurface drainage design in the Konya–Çumra Plain, Turkey

Stripe rust or yellow rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat (Triticum aestivum L.) worldwide. Growing resistant cultivars is the most effective approach to control the disease. There have been numerous reports on the resistance genes to stripe rust (Yr gene) in wheat, but just a few Yr genes are resistant to currently epidemic races and applied in wheat production. Gene pyramiding is considered to be an effective way to enhance durable disease resistance in crops. In this experiment, a panel of Yr gene pyramiding lines (consisting of 3–8 Yr genes) with cv. Chuanyu12 as background parent were constructed by using marker assistant selection and evaluated under currently epidemic Pst races. The results showed that the number of pyramided Yr genes was significant correlated with stripe rust resistance (p < 0.001). Yr15, Yr62 and Yr65 are effective to the current Pst races. Pyramiding more than four effective or partially effective Yr genes can provide enough resistance to stripe rust. And additive effects or epistatic effects existed in gene combinations in this study, such as Yr26 + Yr48, Yr30 + Yr64 and Yr30 + Yr48 et al. Moreover, the effects of Yr gene pyramids on currently prevalent Pst races and agronomic traits were also evaluated, and Yr-gene pyramiding lines with desirable agronomic traits were obtained for durable controlling Pst in wheat breeding.

Developing stripe rust resistant wheat (Triticum aestivum L.) lines with gene pyramiding strategy and marker-assisted selection

SALTMOD is a simulation model whichpredicts root zone soil salinity, drainagewater quality and water table depth inagricultural land under differentgeo-hydrological conditions and varyingwater management scenarios. The model wasapplied to the data from coastal AndhraPradesh of India where subsurface drainagesystem is laid out at several drainspacings at the experimental site. Fielddata for 1999, 2000 and 2001 were collectedfrom 35 and 55 m drain spacing plots forSALTMOD application. Modelling was doneconsidering two simulation approaches. Thefirst approach (Simulation-I) used the sameinitial values for the entire simulationperiod. In the second approach(Simulation-II), the computations wereperformed year-by-year, giving each yearthe current input values obtained from thesimulation results of the previous year.Results of these two approaches weredifferent from each other. Simulation-IIgave better predictions than that ofSimulation-I in terms of closeness to theobserved values. Simulation results ofsoil salinity in the root zone, drainagewater quality and quantity and depth towater table revealed that the salinity ofroot zone was predicted more accuratelythan that of drainage water quality anddepth to water table. Also throughsimulation, it was found that the salinityof drainage water was relativelyindependent of the root zone soil salinity. Model application study suggests thatSALTMOD can be used with confidence toevaluate various drain spacings of asubsurface drainage system and facilitatereasonable prediction of the reclamationperiod.

Application of SALTMOD in Coastal Clay Soil in India

This study was undertaken to pyramid two effective leaf rust resistance genes (Lr19 and Lr24) derived from Thinopyrum (syn. Agropyron), in the susceptible, but agronomically superior wheat cultivar HD2733 using marker-assisted selection. In the year 2001, HD2733 was released for irrigated timely sown conditions of the north eastern plains zone (NEPZ) of India became susceptible to leaf rust, a major disease of the region. Background selection helped in developing near-isogenic lines (NILs) of HD2733 with Lr19 and Lr24 with 97.27 and 98.94%, respectively, of genomic similarity with the parent cultivar, after two backcrossing and one generation of selfing.NILs were intercrossed to combine the genes Lr19 and Lr24. The combination of these two genes in the cultivar HD2733 is expected to provide durable leaf rust resistance in farmers' fields.

Marker-assisted pyramiding of Thinopyrum-derived leaf rust resistance genes Lr19 and Lr24 in bread wheat variety HD2733.

Backcross lines of high yielding cultivar HD2687 developed earlier carrying leaf rust resistance genes Lr19 and Lr28 were utilized to pyramid the two genes using marker assisted selection. Background analysis using 602 SSR markers was done to compare the genotypic background of backcrossed lines with recipient variety HD2687 as well as the donor genotypes Cook*6/C80-1 and CS2A/2M#4/2. Backcross lines of HD2687 with Lr19 and Lr28 i.e. HD2687+Lr19 and HD2687+ Lr28 showed 89 and 92.1 percent genomic similarity with HD2687. The two backcross lines were crossed and plants carrying both Lr19 and Lr28 were identified in F2 generation. Background analysis of 51 plants carrying both Lr19 and Lr28 was undertaken using polymorphic SSR markers to identify plants with better recovery of HD2687 background. Although, Lr19 and Lr28 individually are ineffective against leaf rust pathotypes 77-8 and 77–10 but pyramided lines are expected to provide resistance against all the races.

Mona Singh

Papers

Application of SALTMOD in Coastal Clay Soil in India

Marker-assisted pyramiding of Thinopyrum-derived leaf rust resistance genes Lr19 and Lr24 in bread wheat variety HD2733.

Molecular marker assisted pyramiding of leaf rust resistance genes Lr19 and Lr28 in bread wheat (Triticum aestivum L.) variety HD2687