Spring Crop Season Research Articles

ENHANCING PRE AND POST VEGETATIVE HEAT RESILIENCE AND YIELD POTENTIAL IN THE NEWLY RELEASED MAIZE VARIETY "SAHIWAL GOLD" THROUGH MODIFIED SELECTION

Maize is well-anchored crop across the globe due to its nutritional profile, multipurpose usage, and underlying financial benefits. Growing of open-pollinated maize varieties (OPVs) is a traditional trend and is still followed by a huge community of small farmers in most of the developing world. Improvement in yield potential is always inevitable and requires a purposeful and definite strategy. The current climate scenario loaded with heat escalation and extreme fluctuations is creating uncertainty and unsustainability through acute yield losses in domesticated crops. The breeding strategy of Sahiwal Gold (2008-2018) was comprised of four developmental phases i.e. enrichment phase, half-sib selection, pedigree selection, uniformity phase, and field evaluation at various agro-ecological zones of Pakistan. Each consecutive autumn and spring season was utilized to improve yield potential by exploiting pre and post-vegetative heat resilience. Half sib and pedigree selection improved plant features like height (12%), cob length (4.1%), seeds per cob (7.5%), grain (10%), and stalk yield (11.2%) from enrichment to uniformity phase. Sahiwal Gold maintained a high adaption profile across the tested locations and out-yielded the check variety (MMRI Yellow) by 18% and 26% on average in 6 stations and 16 national yield trials, respectively. National yield testing approved its suitability across provinces like Punjab, Khyber-Pakhtunkhwa (KPK), and Islamabad territory under a diverse range of temperatures. Analysis of variance revealed that highly significant interaction between season and genotypes work for plant height, grain, and stalk yield potential. Higher grain yield up to 95 mounds/acre was observed for spring season crop and batter stalk yield results (650 mounds/acre) were assessed during autumn plantation. Twelve (12) feet tall plants with 4 feet long leaves having 75-90% stay green ability provide a good opportunity fodder and grain yield potential at farmer’s field. This work will provide a better understanding to researchers for designing breeding programs for the development of heat resilience germplasm in crops.

Sericulture in Jammu and Kashmir- A Review

Sericulture is considered as an age old occupation in Jammu and Kashmir. J&K has enormous potential for silk production empowering the farmers of J&K by increasing their income and employment (Dar et al., 2021).The raw silk produced in J&K is recognized across the globe. The size of land holding is less for sericulture activity compared to horticulture and agroforesrty. Farmers from about 20 districts of J&K take sericulture as the subsidiary occupation. Spring season crop (May-June) is the main crop in this region followed by second crop during September- October (Chouhan et al., 2016). Important mulberry varieties cultivated are Goshoerami, Ichinose, KNG, Kukusou 21, Sujanpur and Chak Majra (Shabnam et al., 2016). Silkworm races of commercial importance are DUN22, NB4D2, SK6, SKUAST-31, CSR18 and DUN6 (Buhroo et al., 2017). Sericulture is taken as a subsidiary occupation by about 33,000 rural households in J&K. Most of these families are economically backward and sericulture plays a crucial role for their livelihood. In order to empower these farm families productivity and quality of cocoons need to be improved by applying scientific package of practices. (Bhat et al., 2020). Inadequacy of mulberry leaves and lack of awareness on scientific technologies, ineffective marketing strategies are the hurdles for the progress of sericulture industry in J&K.

Organophosphate Pesticide Exposure: Effect on Farmers’ Sperm Quality in the Mekong Delta, Vietnam

ABSTRACT Objectives Using pesticides in the An Giang province is widespread. However, studies on the health effect of organophosphate pesticide have not been updated within the past 12 years. This study aimed to assess exposure to organophosphate pesticides and their effects on sperm quality among farmers in the An Giang Province, Mekong Delta, Vietnam. Methods During the winter – spring crop season of December 2021 to February 2022, a cross-sectional study was conducted on farmers aged 18 to 60 years-old based on seven communes’ health checkup programs. The pesticide spray group included farmers who had sprayed pesticides in the previous week and had a history of working in agriculture for more than 2 years. The control group was defined as those who lived in the same community, had not worked in agriculture, and had never sprayed pesticides. Demographic characteristics and blood, urine, and semen samples were collected and analyzed. Results Data for 184 eligible participants were analyzed, including 116 farmers in the pesticide spray group and 68 non-farmers in the control group. Pesticide spray contributed to a decrease in the sperm quality index of 6.253 units (95% CI, 4.472–8.749). Increasing each pseudocholinesterase (PChE) unit (kIU/L) was associated with an increase of 1.181 units in the sperm quality index (95% CI, 0.757–0.947). Conclusions Preventive methods for organophosphate pesticide exposure, such as administrative controls, engineering controls, substitution, and personal protective equipment should be applied to control health risks. In the An Giang setting, personal protective equipment is feasible, but most types of equipment are not used. The immediate priority is to determine the cause of personal protective equipment not being used and to find solutions to encourage people to use them.

Deciphering variability for heat tolerance index in maize hybrids and identification of stress resilient heterotic combinations

Aim: High temperature at any critical stage for a prolonged duration is documented to negatively affect the growth and yield related processes in maize. Therefore, the present study was planned to identify resilience of different heterotic combinations to heat stress under field conditions. Methodology: A set of 20 parental lines were used as parents and 21 single cross hybrids raised in kharif 2020 using 16 lines as female parent and four lines as male parent along with three commercial checks using randomized block design under two regimes: Normal Sownin mid of February, i.e., timely sown condition (spring season crop) and late sown in mid of March (heat stress crop). Data was recorded for yield and its contributing traits. Results: Heat stress led to early onset of flowering, thus resulting in shortening of vegetative phase. Consequently, days to grain filling period was found to be reduced (84-106 days) under late sown as compared to 100-123 days under normal sown condition. Amongst the top performing six hybrids in both normal sown and late sown conditions, three hybrids were common viz., JH 20003, JH 20015 and JH 20018, though with different ranking, inferring their wider adaptability and tolerance to heat stress. Under late sown conditions, days to grain filling (r2=0.55) and thousand seed weight (r2 =0.50) showed significantly positive correlation with grain yield while as highly significant and negative association was observed between anthesis silking interval and grain yield (r2 = -0.76). Among the 21 hybrids, three hybrids (JH 20001, JH 20004, and JH 20015) showed greater potential under heat stress conditions on the basis of yield performance under stress, percent yield reduction and heat tolerance index. Interpretation: Based on multiple selection criteria, three hybrids viz., JH 20001, JH 20004, and JH 20015 were suggested for commercial utilization after validation. This study also led to identification of donor inbreds which can contribute to breeding for heat stress tolerance. Key words: Grain yield, Heat tolerance index, Heat stress, Maize, Percent yield reduction

Advantages of altering cropping schedules in the face of climate variability: A case study of Tan Ky sugarcane cultivation area, Nghe An province

Tan Ky is known as one of the sugarcane cultivation regions (SCRs) of Nghe An Province, Vietnam. In recent years, the area is facing adverse weather factors, as a part of climate variability, resulting in a significant decrease in the income of cane growers. The study, therefore, is to estimate the benefits of the sugarcane growing practical (SGP) for the SCRs of Tan Ky district in the background of climate change and further seek effective adaptation solutions as well as optimize profits. Sugarcane yield was evaluated by simulating the APSIM-Sugar model (Version 7.0) based on the soil, crop varieties, field management and climate data during the period of 2000-21. The performance of the proposed model was appraised by comparing the simulated results with observed biomass and sugarcane yield data through the statistical indices with R2=0.83 ÷ 0.86, d=0.80 ÷ 0.88, and RMSE=0.16 ÷ 0.18. Results indicated that under the same cultivation conditions, the SGP in the adverse weather period could lead to a slight decline in the sugarcane yield around 6.8% for spring crop season compared to the favourable weather period. In general, the SGP across the SCRs of Tan Ky district are not suitable for the local cane growers and that may be one of the main causes leading to the decline in sugarcane yield and further decrease in cane growers’ incomes.

Field life tables and key mortality factors of Helicoverpa armigera infesting tomato (Solanum lycopersicon)

Field life table studies of Helicoverpa armigera (Hübner) infesting tomato (Solanum lycopersicon L.) wereundertaken during 2018 and 2019 at research farm of Punjab Agricultural University, Ludhiana, Punjab. Key mortality factors observed in early and late larval instar groups were Campoletis chlorideae (Uchida), Beauveria bassiana (Bals.), HaNPV, Bacillus thuringiensis (Berliner), along with other unknown factors. The egg stage was the most vulnerable exhibiting the highest loss (32.0–91.0%) during main and spring season tomato crop followed by early larval stage (40.27–44.86%), late larval stage (35.84–40.95%), and pupal (24.45–29.23%) stage. Trend index was positive (4.54) on main season crop which showed that total mortality factors during this season were not effective in causing the pest decline and it was negative (0.22) on spring season crop which depicted that total mortality factors were more effective and the chances of increase in population during next season would be less. Generation survival was highest on main season crop (0.29) as compared to spring season (0.23) and indicated that maximum generation survival was in main season whereas, in spring season the generation survival was lower and contributed maximum towards mortality

VRPLK-2: A superior genotype of spinach beet for round the year cultivation

The aim of present study on spinach beet was to evaluatethe performance of best performing genotypes during roundthe year monthly sowing for two consecutive years in theclimes of northern Indian plains at ICAR-Indian Institute ofVegetable Research, Varanasi, Uttar Pradesh. The marketablebiomass yield for VRPLK-2 was realized 136-887 q/ha duringround the year sowing which is 56-147% higher than checkvariety All Green because of faster plant growth, 16-33 daysdelayed-bolting habit and 1-2 more number of cutting(s).Overall, the biomass yield of spinach beet was harvestedmaximum during August to November sowing (Autumn &Winter season crop) followed by December to Februarysowing (Spring season crop) and minimum during March toJuly sowing (Summer & Rainy season crop). Higher biomassyield potential, delayed-bolting habit, faster plant growth,more number of cutting, longer cropping period and wideradaptability to different growing conditions & seasons forgenotype VRPLK-2 make it a unique genotype whosegenetic potential could be utilized in breeding programmesto widen the genetic variability towards delayed boltinghabit and to increase the genotypic adaptability in variedclimates in spinach beet.

Joint forcing of climate warming and ENSO on a dual-cropping system

Challenges for achieving food security with an increasing world population are stimulating many stakeholders to consider the impact of climate change on global-regional crop production. One major concern is how the covariations of climate warming and extremes (e.g., ENSO) affect agricultural systems and production. Here, a dual-cropping system in the Huaihe Plain was used as a testbed to address this issue. We found that climate warming during 1982–2013 has produced remarkable influences on the dual-cropping agricultural system. For the spring season crop (i.e., winter wheat), a significant negative effect was found with a production loss of ˜6.9 × 106 tons due to an elevated Tmean (˜2.21 °C) (r=-0.508, p < 0.01), which was associated with water stress. For the summer/autumn crops (i.e., rice and maize), a significant positive effect was found, but with a less substantial production gain (˜1.4 × 106 tons), supposedly due to the relaxed temperature constraints (an increased Tmax of ˜1.28 °C) for high heat resistant crops (r = 0.495, p < 0.01). The phenophase of the crop growing period was shortened by ˜7 days for the spring crop and by ˜4.4 days for the summer/autumn crops with enhanced thermal conditions. Precipitation anomalies, especially those associated with ENSO turning from El Niño to La Niña, imposed an additional serious impact on the dual-cropping system through decreased precipitation in the spring and increased precipitation in the summer/autumn. Potential impacts for the future could be derived from intensification of water and heat stresses, as well as the climate extremes (e.g., ENSO and AAO).

Stability comparison of parental and modified double cross maize hybrids

The objective of this study was to study the level of grain yield reduction in modified double cross maize hybrids in comparison with their parental hybrids. Yield performance and stability comparison for yield and yield associated parameters for modified double cross maize hybrids and their respective standard parental hybrids was carried out across three locations of Khyber Pakhtunkhwa i.e., The University of Agriculture (UAP), Agricultural Research Station (ARS) Baffa (Mansehra) and Cereal Crops Research Institute (CCRI), Pirsabak (Nowshera), during 2009-10. Modified double cross hybrids of maize having improved yield were produced during spring crop season 2009 at Malakandher Research farm of University of Agriculture, Peshawar. Genotype x environment interaction was studied for yield and yield parameters in five modified double cross maize hybrids and their respective parental maize hybrids. Genotype main effect and genotype x environment interaction effect revealed significant differences for all parameters, except grain moisture at harvest which exhibited non-significant differences. Based on stability parameters and over all mean, the performance of modified double cross hybrid WD-2x8 across different environments excelled other parental hybrids as well as modified hybrids. Selection of modified hybrid WD-2x8 for ear length, ear diameter, 300 kernel weight and grain yield could enhance the grain yield in the target environments and it could be recommended as suitable and stable genotype for locations similar to the target environments. It can be inferred that the production of modified double cross hybrids could be beneficial, as the yield of modified double cross hybrids were almost at par with their respective parental maize hybrids. Keywords: Finlay-Wilkinson stability analysis; Modified double cross maize hybrids; Yield and yield related traits http://dx.doi.org/10.19045/bspab.2017.60003

Plant Arrangement Effect on the Sunflower Yield and Yield Traits in Spring Season Crop

Plant Arrangement Effect on the Sunflower Yield and Yield Traits in Spring Season Crop

English

A fixed plot field experiment was carried out during 2008-09 and 2009-10 at New Delhi, India to study the “effects of sunflower stover, nitrogen and phosphorus management on soil health under pigeonpea-sunflower cropping system’’. Kharif season experiment in the first year was laid out in split-plot design, assigning sunflower stover incorporation (8 t/ha) and no stover incorporation (control) to main plots and combination of P levels and bio-fertilizers {control, 15 kg P/ha, 15 kg P/ha + phosphate solubilizing bacteria (PSB), and 30 kg P/ha} to sub-plots. The spring season experiment of both years was laid out in split-split plot design in which NP doses to sunflower crop {control, 50% recommended dose (RD) of NP, and recommended dose (RD) of NP (80 kg N + 15 kg P/ha} were applied in sub-sub plots. Kharif season experiment in the second year was laid out in split-split plot design to investigate the residual effect of NP doses applied to spring season crop in sub-sub plots. Treatments were replicated thrice during both years. Results reveal that the sunflower stover incorporation resulted in better soil biological properties in terms of dehydrogenase activity, alkaline phosphatase activity and microbial biomass carbon (MBC). Available soil NH4-N and NO3-N, available P initially reduced due to sunflower stover incorporation but at latter stages, these nutrients in soil increased. Among the various P levels, application of 30 kg P/ha recorded maximum values of soil dehydrogenase, MBC and available P, NH4-N and lowest values of alkaline phosphatase and NO3-N. With respect to the residual effect of nitrogen and phosphorus applied to sunflower, among the various levels of N and P, recommended dose (RD) of N and P resulted in better soil biological properties under study and higher values of available N and P. Key words: Available nutrients, biological properties, cropping system, nutrients management, sunflower stover management.

Individual lift irrigation: a case study in the Cau Son irrigation and drainage area, Red River Basin, Vietnam

The irrigation trend in Asia has been characterised as a shift from gravity to lift irrigation, but the importance of individual lift irrigation using surface water remains to be documented. Surveys on field water application by farmers using lift were undertaken in three sites and across the 44,600 ha Cau Son irrigation and drainage area in the spring crop season. Lift irrigation was found to be practised by 82 % of households. The main lift technology was mechanical pump (petrol and electric), followed by traditional swing and long-handle baskets. The main source for lifting was on-farm canals. Although gravity irrigation was the dominant field application method, the area solely irrigated by individual lift ranged from 25 to 52 % of the irrigated areas. Scaling up from the sites, individual lift accounted for 29 % by irrigation area and volume, with 17 and 12 % attributed to mechanical and manual lift. The application of mechanical pumps was a response to locally high-field elevations and significantly increased with the distance of water delivery from the main canal. The impact of mechanical pumping on flexibility and reliability was significant and positive. Petrol driven pumps had relatively high operational and investment costs, but farmers gained higher flexibility and reliability and compensated by applying less water. Farmers using electric pumps applied significantly more water and thereby wasted electric energy as a compensation for uncertain electric power supply. The importance of individual lift irrigation suggests that it should be explicitly considered in irrigation management policies and performance assessments.

Change in heritability estimates due to half-sib family selection in the maize variety Pahari

This research was carried out at the Agriculture Research Farm, Khyber Pakhtunkhwa Agricultural University, Peshawar, and the Cereal Crops Research Institute, Pirsabak, Nowshera, during 2009 and 2010. Half-sib families (HS) derived from the maize variety Pahari in spring crop seasons 2009 and 2010 were developed at the Cereal Crops Research Institute. All HS families were detasseled well before pollen shedding. At maturity, each family was harvested and shelled separately. During the summer crop of seasons 2009 and 2010, these HS families were evaluated in 12 x 12 and 11 x 11 partially balanced lattice square arrangements at the Khyber Pakhtunkhwa Agricultural University, Peshawar, for various flowering and yield traits, respectively. The data on days to mid-silking, anthesis, anthesis-silking interval, 100-grain weight, and grain yield were recorded. The results revealed significant differences among families for all traits in both cycles. High heritability (0.88) was observed for days to mid-silking in cycle 0 (C₀), while moderate heritability (0.42) was recorded for 100-grain weight in C₁. The selection differential was quite reasonable and varied according to the traits of interest. The observed response for grain yield in C₀ (815.74 kg/ha) was greater than the expected response (681.76 kg/ha).

Efficacy of Bacillus-fortified organic fertiliser in controlling bacterial wilt of tomato in the field

Ralstonia solanacearum (Smith) has been a severe pathogen on tomato worldwide and no effective control measure is available yet. To develop a new bio-product for controlling this disease, antagonistic Bacillus amyloliquefaciens strains QL-5 and QL-18 were isolated from rhizosphere soil of tomato and used separately or together to fortify organic fertilisers to control bacterial wilt of tomato (BWT), both in the greenhouse and in the field. The bio-organic fertiliser (BOF) fortified with a mixed inoculation of QL-5 and QL-18 effectively decreased R. solanacearum disease incidence in both greenhouse and field conditions. However, the suppressive efficacy in the field depended on the season. Disease incidence in the spring crop season in 2009 and 2010 was significantly reduced, while a low suppressive effect was observed in the autumn crop season in 2008 and 2009. The initial R. solanacearum population in the soil was nearly three times lower in the spring before transplanting seedlings than in the autumn crop season. The pathogen population in the field was positively and significantly correlated with air temperature but was not correlated with relative humidity. The interaction between BOF and other soil and climatic factors that affect pathogen density in the field should be clarified.

A Survey of Tomato and Potato Fields in Florida Reveals Unique Genotypes of Phytophthora infestans between 2005 and 2007

Late blight, caused by Phytophthora infestans, affects tomatoes and potatoes in Florida during the winter–spring crop season. During the 2005 season, severe late blight epidemics were observed in Florida prompting our survey. Isolates from 2005 to 2007 were characterized phenotypically based on growth on three media, mating type, pathogenicity, and sensitivity to metalaxyl and genotypically based on two isozymes, mitochondrial DNA (mtDNA), and genomic profiling using the RG57 probe. Isolates collected in this survey were all A2, mtDNA Ia, and either 100/100 (2005), or 100/122 (2006/2007) at the Gpi locus, and homozygous 100 at the Pep locus. Novel genotypes infecting tomato in Florida were observed based on the Gpi locus and RG57 genomic profile. We propose US-20 for the collection of clonal isolates recovered during the 2005 season and US-21 for clones recovered during 2006 and 2007. In addition to these novel genotypes recovered from tomato, one isolate was recovered from potato representing the US-8 clonal lineage. The findings of the survey in south Florida and their implications are presented.

Influence of Spring Season Crop Residue on Productivity of Rice-Wheat Cropping System

A field experiment was conducted to determine the effect of cultivation and plant residue incorporation of blackgram [Vigna mungo (L.) Hepper], mungbean [Vigna radiata (L.) Wilczek], cowpea (Vigna sinensis L.), maize (Zea mays L.) and maize+blackgram on response of rice to two levels (0 and 90 kg ha-1) of nitrogen and their residual effects on nitrogen management of subsequent wheat crop. The experiment was carried out in Randomized Complete Block design in spring, Split Plot design in rainy, and Split-Split plot design in winter seasons of 2000 at Institute of Agriculture and Animal Science (IAAS), Rampur, Chitwan, Nepal. Results showed that cultivation and incorporation of different spring season crop’s (legume and cereal) residue into the soil did not significantly affect rice yield. Such trend was also observed on wheat grain yield when spring season crops were followed by rice in a sequential cropping system. Significantly higher (p&lt;0.001) rice equivalent yield (6.56 t ha-1) and net profit (Rs. 46489 ha-1) were obtained under mungbean-rice sequence. Similarly, significantly higher (p&lt;0.001) wheat equivalent yield (8.74 t ha-1) and net profit (Rs. 44811 ha-1) were obtained under mungbean-rice-wheat sequence. Significantly higher yield of rice was obtained under 90 kg N ha-1 compared to control and had significant residual effect of N on wheat grain yield. Nitrogen topdressed at crown root initiation (CRI) and panicle initiation (PI) stages did not influence significantly on the grain yield of wheat. Therefore, for the long term sustainability of rice-wheat cropping system, inclusion of mungbean in the spring (fallow) season could be considered promising practice.&#x0D; &#x0D; Key words: Rice-wheat cropping system, sustainability, residue incorporation, nitrogen&#x0D; &#x0D; J. Inst. Agric. Anim. Sci. 27:53-58 (2006)

Toward Integrated Management of Monosporascus Wilt of Melons in Israel.

The phenomenon of melon wilting dueto Monosporascus infection (Fig. 1) isknown in many regions around the worldand has been referred to as melon collapse(13,27,32,38), sudden wilt (2,6,8,26,29),root rot (17,39), vine decline (1,3,36), androot rot and vine decline (21–23,41,42).This disease is known also in the ’AravaRift Valley of southern Israel (8,19,26,31;Fig. 2), and the major causal agent isMonosporascus cannonballus Pollack &Uecker (Fig. 3). This pathogen is commonin hot, semiarid melon-growing areas ofIndia (22), southern Spain (13), southwest-ern regions of the United States (23,24,36),Saudi Arabia (15), Central America (1),Japan (40), Taiwan (37), and Tunisia (21).This disease in the ’Arava can be verysevere, capable of destroying the entirecrop (26), and will be referred to here asMonosporascus wilt. To date, disease man-agement in the ’Arava (38) has beenmainly based on methyl bromide fumiga-tion of the soil prior to planting. Sincemethyl bromide use will be prohibited inthe near future (33), there is an urgent needto develop alternative strategies for diseasemanagement.Melon root rot and vine decline causedby M. cannonballus has been reviewed in afeature article by Martyn and Miller (22),which describes the biology, pathology,and epidemiology of the disease, as well asmolecular methods for detecting variationin the pathogen population. In this article,we discuss approaches for the control ofMonosporascus wilt, with an emphasis onthe potential for integrated management, inview of the coming phaseout of methylbromide. These approaches include breed-ing for resistance, grafting melon plantsonto resistant Cucurbita and melon root-stocks, changes in irrigation schemes, im-proved soil solarization, chemical controlwith fungicides, and the use of other fumi-gants, alone or combined with soil solari-zation, to improve disease control.In field trials conducted by Reuveni andKrikun in the Jordan Valley and southern’Arava region in Israel (Fig. 2) in the early1980s, it was shown that Monosporascuseutypoides (apparently synonymous withM. cannonballus) is the primary agent ofmelon collapse (19,31). Pathogenicity testsperformed in 1995 and 1996 suggested thatthe most virulent species involved in themelon collapse syndrome in the ’Arava(Fig. 2) is M. cannonballus, although otherpathogens might also be involved (26).Monosporascus appears to be adapted tohot climates. This can be inferred from theclimatic conditions in the areas in whichthe fungus has been found and by itsgrowth temperature optimum. Vegetativemycelial growth is extensive in the rangeof 25 to 35°C, and perithecia formation invitro is optimal at 25 to 30°C (22).In commercial fields in Israel, the meloncrop can be totally destroyed by Monospo-rascus wilt in the autumn cropping season,whereas disease incidence and severity in acrop raised in the same plot during thefollowing winter–spring season can bemuch lower (2). Differences in soil tem-perature between crop seasons have beensuggested as a possible cause for such aphenomenon (17,28). This idea has beensupported by enhanced wilting obtainedfollowing artificial heating of the soil dur-ing the winter–spring crop season (28).Soil fumigation with methyl bromidebefore planting is the most common ap-proach for controlling Monosporascus wiltof melons in Israel. Methyl bromide haslethal exposure periods as short as 2 daysand can be applied at relatively low tem-peratures. The aeration period to eliminatevolatile residues before planting is short inmost soils, 3 to 10 days, allowing plantingshortly after treatment (18). In fact, meloncultivation in the ’Arava region is ex-tremely risky without methyl bromidefumigation prior to planting, due to theubiquity of M. cannonballus in ’Aravasoils that results in severe yield losses. Thephaseout of methyl bromide in developed

WATER AND FERTILIZER MANAGEMENT OF MICROIRRIGATED FRESH MARKET TOMATOES

ABSTRACT Field studies were conducted to evaluate water and fertilizer management for fresh market tomato production on raised, plastic mulched beds using microirrigation with buried drip lines on a sandy soil. The studies were additionally designed to compare microirrigated tomato production with the typical subirrigation (seepage) production and to provide local growers with management guidelines. Tests were evaluated during two fall crop seasons and one spring crop season. Tensiometers placed at 0.15 m depths were manually monitored and used to aid with irrigation scheduling. Two soil water management levels were used to evaluate a low moisture management (LMM) treatment which was scheduled to maintain soil water tensions no drier than 10 to 15 kPa, and a high moisture management (HMM) treatment which was operated similar to current grower practice and provided water to maintain soil water tensions between 5 and 10 kPa. Two treatment levels of seasonal nitrogen (N) and potassium (K) applications were used to evaluate low (reduced) fertihzer (LF) applied at 224 and 372 kg/ha of N and K and high fertilizer (HF) applied at 336 and 558 kg/ha ofNandK. Spring crop production yields and water requirements were greater than those associated with the fall season. Yields from the HMM schedule were greater than those for the LMM schedule during the spring crop, but not during either of the two fall crops. In addition, the HMM schedule during the spring crop increased the proportion of extra large fruit. Yields from microirrigated plots were equivalent to those from the subirrigated (seepage) plots. No significant benefit was realized by using the HF vs. LF levels of fertilizer from either of the fall crops or from the spring crop. Thus, spring production of microirrigated fresh market tomatoes requires more water than fall production, yet yields are higher and response to irrigation management is more sensitive than fall season production. Improved water and fertilizer management by using tensiometers and fertigation with microirrigation of fresh market tomatoes produced on sandy soils can result in reduced water and fertilizer applications as compared to those associated with current subirrigation (seepage) methods. KEYWORDS. Microirrigation, Tomatoes, Fertilizer.

Yield stability of induced-early-maturing mutants of mungbean ( Vigna radiata) and their use in a multiple-cropping system

The performance of seven mutants of mungbean along with parental types was studied at 41 different sites in three summer crop seasons from 1980 to 1982. The performance of mutants was also studied in spring in the fallow period preceding cotton, and in early summer in the fallow period between wheat harvest and rice/maize planting, to assess their suitability of growing as a catch-crop in these fallows. The mutants yielded significantly higher and matured 2–4 weeks earlier than parental types, leaving sufficient time to sow the succeeding crops. The mutants were characteristically short-statured, and superior to their parents with respect to number of pods per plant, seed weight, harvest index and productivity per day, but similar in numbers of seeds per pod and seed protein content. The stability of yield was estimated through regression analysis. Significant genotypic differences were observed among mutants and varieties. Some mutants were widely adapted whereas others performed better in favourable environments. The parental types tended to respond well under poor environments. Owing to their higher yield potential, early and uniform maturity, and wide adaptability, four mutants were approved as commercial varieties in 1986. These mutants yield 30–50% higher than the parents, mature in 55–70 days, and are suited to both summer and spring crop seasons. Of these four mutants, two can be grown in the fallow period between wheat harvest and rice/maize planting. Because of their determinate plant type, non-shattering pod and top fruit-bearing habit, these mutants are also amenable to intercropping practices and mechanised harvesting operations. The role of induced mutations for the improvement of mungbean is discussed.