Cauliflower Curd Research Articles

Alternatively spliced BobCAL transcripts alter curd morphotypes in a collection of Chinese cauliflower accessions

The curd of cauliflower (Brassica oleracea L. var. botrytis) is a modified inflorescence that is consumed as a vegetable. Curd formation is proposed to be due to a mutation in the BobCAULIFLOWER (BobCAL) gene, but the genetic relationship between BobCAL variation and curd morphotypes remains obscure. To address this question, we collected and classified a collection of 78 cauliflower accessions into four subpopulations according to curd surface features: smooth, coarse, granular, and hairy curd morphotypes. Through the cDNA sequencing of BobCAL alleles, we showed that smooth and coarse accessions characterized by inflorescence meristem arrest presented a strong association with the 451T SNP (BobCAL_T), whereas granular and hairy accessions marked with floral organ arrest presented an association with 451G (BobCAL_G). Interestingly, all BobCAL alleles were alternatively spliced, resulting in a total of four alternative splice (AS) variants due to the retention of the fourth and/or seventh introns. Among accessions with BobCAL_G alleles, the total expression of all these AS variants in granular plants was almost equal to that in hairy plants; however, the expression of the individual AS variants encoding intact proteins relative to those encoding truncated proteins differed. Hairy accessions showed relatively high expression of the individual variants encoding intact proteins, whereas granular accessions displayed relatively low expression. In smooth cauliflower, the overexpression of the BobCAL_Ga variant caused an alteration in the curd morphotype from smooth to hairy, concurrent with an increase in the expression levels of downstream floral identity genes. These results reveal that alternative splicing of BobCAL transcripts is involved in the determination of cauliflower curd morphotypes.

Soil salinity control and cauliflower quality promotion by intercropping with five turfgrass species

Greenhouse vegetable production contributes 60% of the economic value of the world vegetable industry. However, the secondary soil salinization and nitrate accumulation in vegetable products have become critical concerns in greenhouse vegetable production system. Here we show that cauliflower intercropped with five turfgrass species not only reduces the salinity stress and nitrate accumulation of cauliflower but also improves cauliflower curd quality. Effect of soil salinity control and cauliflower nitrate reduction was associated with the capacity of salt and nitrate uptake and accumulation of turfgrass species. Paspalum vaginatum performed the most significant effects on soil salinity control, reduced 37.8% of nitrate content, increased 50.7% of vitamin C and 21.1% of soluble protein contents in cauliflower curd. Our results demonstrated that intercropping with Paspalum vaginatum could provide a significant help for the sustainable development in the intensive greenhouse vegetable production.

Identification of Candidate Genes Involved in Curd Riceyness in Cauliflower.

“Riceyness” refers to the precocious development of flower bud initials over the curd surface of cauliflower, and it is regarded as undesirable for the market. The present study aimed to identify the candidate loci and genes responsible for the morphological difference in riceyness between a pair of cauliflower sister lines. Genetic analysis revealed that riceyness is controlled by a single dominant locus. An F2 population derived from the cross between these sister lines was used to construct “riceyness” and “non-riceyness” bulks, and then it was subjected to BSA-seq. On the basis of the results of Δ(SNP-index) analysis, a 4.0 Mb candidate region including 22 putative SNPs was mapped on chromosome C04. Combining the RNA-seq, gene function annotation, and target sequence analysis among two parents and other breeding lines, an orthologous gene of the Arabidopsis gene SOC1, Bo4g024850 was presumed as the candidate gene, and an upstream SNP likely resulted in riceyness phenotype via influencing the expression levels of Bo4g024850. These results are helpful to understand the genetic mechanism regulating riceyness, and to facilitate the molecular improvement on cauliflower curds.

Genetics and Expression Analysis of Anthocyanin Accumulation in Curd Portion of Sicilian Purple to Facilitate Biofortification of Indian Cauliflower.

The present study was undertaken to know the genetics of purple color of cauliflower curds using a Sicilian purple ‘PC-1’ and a white curding mid-late group genotype of Indian cauliflower. For this, a cross was attempted between ‘DC-466’ (white curd) and ‘PC-1’ (purple curd) and observed intermediate level of purple pigmentation on curds in F1 plants. Segregation of F2 population (173) revealed that the purple color of the curd was governed by a single gene dominant over white, but the expression of trait was incomplete. It was substantiated by segregation of plants of BC1 and F2:3(intermediate) generations into 1(white):1(intermediate) and 1(white):2(intermediate):1(intense), respectively. The F2, B1, and B2 generations segregated into purple(intermediate to intense): white curding plants in the ratio of 126: 47, 26:24, and 40:0, respectively fitting well with the Mendelian ratio of single gene for purple curds. However, purple pigmentation on curds ranged from very light to intense, which corroborated with the wide range of anthocyanin content in F2 (3.81–48.21 mg/100 g fw). Out of three molecular markers from high resolution map of Pr gene in purple color cauliflower ‘Graffiti’, only BoMYB3 marker could distinguish purple and white curding parents but did not show co-segregation while investigated in F2 population. Expression of BoMYB1 gene was up regulated in both the purple curd genotypes ‘PC-1’ and ‘Graffiti’ in comparison to white curded ‘DC-466’, while BoMYB2 gene was slightly upregulated in ‘PC-1’ but down regulated in ‘Graffiti’. Occurrence of ‘broccoli type’ F2 individuals and their genetic stability in F2:3 support the intermediate position of ‘Sicilian purple’ between broccoli (Calabrese) and cauliflower. There was not any correlation between curd coloration and pigmentation on apical leaf and stem portion, indicating difference of expression in ‘PC-1’ than ‘Graffiti’. The information obtained is useful for breeding anthocyanin rich attractive purple curding ‘specialty cauliflower’ for better consumer health and growers’ earnings.

Evaluation of cauliflower genotypes by different growing method

Cauliflower is currently cultivated on 350-400 thousand hectares in the world and around 1500 ha in Hungary. Its cultivation requires considerable expertise as it is sensitive to environmental factors and adequate nutrient supply. The aim of our experiment was to compare three genotypes (Abeni, SV5777 AC and Telergy F1) by different growing method – under plastic tunnel and on open field. On open field the planting was on 19th of March, 2018, the row and plant distances were 45 and 35 cm. Under plastic tunnel the transplants were set out on the same day with the same genotypes as on open field, with 55x45 cm arrangement. The results have proved that cauliflower curds from plastic tunnel was two times bigger than on open field. The more protected environment had a positive effect not only on the mass of the curd, but also on the biomass production. Among the examined genotypes Abeni showed the highest yield (about 1 kg/plant) under plastic tunnel. The shape of the head is important for the market. According to our data, we measured the width and height of the curd. Open field conditions induced wider curd with longer stem and caused lower product quality and weaker correlation between the parameters than plastic tunnel.

Cauliflower Growth, Yield and Quality Response to Nitrogen Fertilization and Micronutrients Foliar Application in Newly Reclaimed Areas

Two field experiments were carried out during 2017/2018 and 2018/2019 seasons, at the Experimental Farm, Faculty of Agriculture, New Valley University, New Valley governorate, Egypt, to study the effect of nitrogen levels (30, 45 and 60 kg/fed.) and micronutrients foliar application: control (B 0 + Mo 0), boron at 100 ppm (B 100), molybdenum at 50 ppm (Mo 50) and combined boron and molybdenum (B 100 + Mo 50) on cauliflower vegetative growth, yield, and quality parameters in the recently reclaimed areas, especially New Valley governorate as a promising area for agriculture expansion in Egypt. The results revealed that nearly all traits showed a gradual increment with increasing the nitrogen level; whereas the application of high level of nitrogen (60 kg/fed.) significantly increased vegetative growth, curd yield and curd quality of cauliflower and significantly decreased total phenols content and has no effect on number of days to maturity. Also, the results of this study reported promotional effects of either B or Mo foliar application on growth, yield and quality of cauliflower curds compared with untreated plants; nevertheless the combined application of B and Mo together was more effective than application of B or Mo when they separately applied. Moreover, inorganic nitrogen at 60 kg/fed. was more effective in the presence of B and Mo at 100 and 50 ppm, respectively, than the other combinations and achieved the highest curd yield with top quality.

Correlation of curd‐associated fungi with NPK and Na concentrations in cauliflower

AbstractUnderstanding relations among nutrients and fungi infestation may help to produce fungi‐free cauliflower curds by managing plant nutrition. Structural equation modeling was used to express correlations among curd‐associated fungi and NPK and Na concentrations in 66 curds collected from 22 fields. Five out total nine isolated fungi were found correlated with the nutrients and Na as suggested by final fitted model. The model expressed 7–30% occurrence of the fungi because of estimated factors. In general, fungi infections were favored with nitrogen, phosphorus, and sodium concentrations whereas discouraged with potassium. The model highlighted the synergistic effect of Fusarium avenaceum and Aspergillus fumigatus on the occurrence of Fusarium polyphialidicum and Aspergillus nigar, respectively, and an antagonistic effect of A. nigar on Alternaria brassicicola. The findings indirectly discourage overdose of N and P, whereas encourage application of K and reclamation of sodic soils to reduce fungi infestation of cauliflower.Practical applicationsMicrobial analysis of cauliflower will help in recognizing possible fungal contaminants of apparently healthy curds. Relationship of these curd‐associated fungi with NPK and Na status of curds will highlight the importance of managing macronutrient fertilizers and reclamation of sodic soils in fungi‐free cauliflower production.

SPAD index in the diagnosis of nitrogen status in cauliflower as a function of nitrogen fertilization

The correct management of fertilization in cauliflower crop can be obtained by synchronizing the plant demand with the N supply during the crop cycle. There is no study indicating that the SPAD index can be used in the eval­uation of nitrogen nutrition of cauliflower. Thus, the objective of this work was to evaluate the nitrogen nutritional status of cauliflower using the SPAD index, and curd yield as a function of nitrogen fertilization. Four rates of N in topdressing (0, 150, 300, and 450 kg ha -1 ) were evaluated in the experimental design of randomized blocks with four replicates. The final harvest of curds occurred from 68 to 76 days after transplanting. The first- and second-year results showed a significant difference. Curd fresh mass showed a quadratic adjustment, with the maximum value of 1,435 and 1,611 g, estimated with the rates of 331 and 307 kg ha -1 N, in the first and second year, respectively. The critical levels for leaf total N content were between 48.4 and 57.8 g kg -1 ; and for SPAD units, between 55.90 and 66.63. The nitrogen nutritional status of cauliflower can be estimated using the SPAD index. The critical level for the SPAD index and leaf N content varied from year to year. Higher production of cauliflower curd fresh mass can be obtained with the application of N rates higher than currently recommended.

The effects of plant density and irrigation on phenolic content in cauliflower

This study was conducted to study the influence of plant density and irrigation on the content of phenolic compounds, i.e., phenolic acids and flavonols in cv. ‘Sevilla’ cauliflower curds. Levels of phenolic acids and flavonols were in the range of 3.0–6.2 mg and 25.4–87.8 mg/100 g of dry weight, respectively, depending on plant density and irrigation. Of the phenolic acids, caffeic acid was detected in the highest amount, followed by p-coumaric acid, sinapic acid, gallic acid, and ferulic acid. Of the two flavonols detected, the levels of quercetin were higher than those of kaempferol. The content of the detected phenolic acids (with the exception of ferulic acid) and both flavonols increased with increasing plant density. Furthermore, the concentration of phenolic compounds (with the exception of ferulic acid) was significantly higher under irrigation.

Persistence of premix profenofos and cypermethrin in cauliflower

Persistence of profenofos and cypermethrin was studied on cauliflower after application of their individual as well as ready-mix formulations. Profenofos and cypermethrin were applied at recommended rate 400 g and 40 g a.i./ha and at double the recommended rate 800 g and 80 g a.i./ha. Profenofos and cypermethrin residues in curds reached below the limit of determination in 10 and 5 days when applied at recommended rate and in 15 and 7 days when applied at double the recommended rate. Profenofos deposits in ready-mix formulation treatment, reduced to half in 1.73–2.13 days and cypermethrin deposits required 0.91–1.37 days to reduce to half but when applied individually, profenofos initial deposits were reduced to their half in 1.78–2.21 days and cypermethrin deposits became half in 1.06–1.42 days. In soil, residues of profenofos persisted up to 10 days, whereas residues of cypermethrin were below detectable limit in 10th day sampling in individual insecticides. Therefore, safe waiting period of one day is suggested for ready-mix as well as for individual insecticides at recommended and double the recommended rate on cauliflower curds.

Biometric properties and selected chemical concentration of cauliflower influenced by wastewater applied through surface and subsurface drip irrigation system

The necessity of municipal wastewater reuse for irrigation has become imperative for water scarce countries. It is also supportive to limit the environmental pollution. Field experiment was conducted to investigate the biometric properties of the cauliflower crop and its chemical concentration. To limit the entry of heavy metal elements into the food chain, crop was irrigated through drip irrigation system with municipal wastewater. It was treated though three different type filtration processes viz., sand media type, disk type and combined sand media and disk type filters under surface and subsurface placement of drip laterals. Highest leaf area index and curd yield was recorded under subsurface placement of drip laterals at 15 cm depth but highest root length density was recorded under subsurface placement of drip laterals at 30 cm depth. The curd yield was increased by 5% under municipal wastewater irrigation with the saving of 28.3%, 21.1%, and 38.3% of Nitrogen, Phosphorus, and Potassium nutrients, respectively, over groundwater use. Significantly higher concentration of heavy metal elements Arsenic, Cupper, Chromium, Iron, Manganese, Lead, and Zinc was recorded by using municipal wastewater for irrigation over groundwater. However, concentration of all the heavy metals found in the curd of cauliflower was lower than their permissible limit as prescribed by the Food and Agriculture Organisation/World Health Organisation and Indian standards. This study provides an opportunity to utilize municipal wastewater through subsurface placement of drip laterals. It will protect our environment from wastewater pollution with the saving of inorganic fertilizers and fresh water that can be utilized in other priority sectors.

A Single Amino Acid Substitution in an ORANGE Protein Promotes Carotenoid Overaccumulation in Arabidopsis.

Carotenoids are crucial for plant growth and human health. The finding of ORANGE (OR) protein as a pivotal regulator of carotenogenesis offers a unique opportunity to comprehensively understand the regulatory mechanisms of carotenoid accumulation and develop crops with enhanced nutritional quality. Here, we demonstrated that alteration of a single amino acid in a wild-type OR greatly enhanced its ability to promote carotenoid accumulation. Whereas overexpression of OR from Arabidopsis (Arabidopsis thaliana; AtOR) or from the agronomically important crop sorghum (Sorghum bicolor; SbOR) increased carotenoid levels up to 2-fold, expression of AtOR(His) (R90H) or SbOR(His) (R104H) variants dramatically enhanced carotenoid accumulation by up to 7-fold in the Arabidopsis calli. Moreover, we found that AtOR(Ala) (R90A) functioned similarly to AtOR(His) to promote carotenoid overproduction. Neither AtOR nor AtOR(His) greatly affected carotenogenic gene expression. AtOR(His) exhibited similar interactions with phytoene synthase (PSY) as AtOR in posttranscriptionally regulating PSY protein abundance. AtOR(His) triggered biogenesis of membranous chromoplasts in the Arabidopsis calli, which shared structures similar to chromoplasts found in the curd of the orange cauliflower (Brassica oleracea) mutant. By contrast, AtOR did not cause plastid-type changes in comparison with the controls, but produced plastids containing larger and electron-dense plastoglobuli. The unique ability of AtOR(His) in mediating chromoplast biogenesis is responsible for its induced carotenoid overproduction. Our study demonstrates OR(His/Ala) as powerful tools for carotenoid enrichment in plants, and provides insights into the mechanisms underlying OR(His)-regulated carotenoid accumulation.

Effect of sewage sludge and fertilizers on accumulation of micronutrients and yield of cauliflower (Brassica oleracea var botrytis) in an alluvial soil

A field experiment was conducted at Bichpuri (Agra) during rabi seasons of 2007-08 and 2008-09 by using treated sludge along with fertilizer levels to study the effect on yield and accumulation of heavy metals in cauliflower [(Brassica oleracea var botrytis (L.)] and soil. The eight manurial treatments consisted of inorganic and organic sources (treated sludge and FYM) of nutrients. Application of 10 tonnes sludge/ha significantly enhanced the yield and dry matter of cauliflower curd by 36.0 and 36.8% over control, respectively. Increasing levels of NPK fertilizers up to 150% increased the mean curd yield, dry matter yield, content and uptake of elements significantly over control. The maximum curd (33.08 and 28.71 tonnes/ha) and dry matter yields (11.39 and 9.86 tonnes/ha) were recorded under 100% NPK + 10 tonnes treated sludge/ha and minimum (10.83 and 10.45 tonnnes/ha and 3.68 and 3.54 tonnes/ha) under control in first and second year, respectively. Therefore, for the higher productivity of cauliflower about 50% NPK fertilizers could be replaced with addition of treated sludge. Application of 100% NPK + 10 tonnes sludge/ha resulted in the maximum contents of heavy metals in cauliflower curd over control and sludge treated soil. The content of Pb only in curd exceeded the threshold values but no reduction in yield was noted. The highest uptake of Fe (1364 g/ha), Mn (428 g/ha), Cu (121 g/ha), Zn (396 g/ha), Cd (6.1 g/ha) Ni (6.9 g/ha), Pb (52.2 g/ha) and cobalt (7.2 g/ha) by cauliflower curd was recorded under 100% NPK + 10 tonnes sludge/ha. Soil amended with sewage sludge alone resulted in significant build-up of DTPA-extractable micronutrients and heavy metals over control. Combined use of 100% NPK + 10 tonnes sludge/ha resulted in further build–up of micronutrients and heavy metals over sludge treated soil. Thus, it can be concluded that use of sewage sludge can be followed as a good supplement of nutrients for crop production, but care should be taken for the presence of heavy metals and pollutants.

PLANT ABIOTIC STRESS TOLERANCE ANALYSIS IN CAULIFLOWER USING A CURD MICROPROPAGATION SYSTEM

An effective protocol for cauliflower micropropagation was optimised and developed which enabled the production of tens of thousands of cauliflower microshoots from one cauliflower curd. The large number of microshoots that can be produced per culture unit facilitates the use of this protocol to analyse both the physiological and molecular components of abiotic stress tolerance. The protocol was used for cauliflower cold tolerance analysis and it was demonstrated that low temperature acclimation increased the cold tolerance of explants. The effect of two additives used with the cauliflower culture media on cold tolerance were evaluated. ABA significantly decreased both cold tolerance in acclimated and non-acclimated cauliflower microshoots whilst molybdenum had a highly positive effect on cold tolerance of cauliflower microshoots. Moreover, molybdenum had the capacity to increase the cold tolerance of cauliflower microshoots without low temperature treatment. This is the first study that confirmed this feature of molybdenum and it is believed that this finding could have an application in the field.

6-Benzylaminopurine affects lipid peroxidation and membrane permeability and thereby preserves curd quality and antioxidants during storage of cauliflower

Cauliflower curd has a relatively short postharvest life and develops unpleasant odour and browning within a short period. A few low-temperature-linked attempts, with limited success, have been made. However, in most of the countries, it is not stored under cold temperature at practical levels. On the other hand, no study has been carried out to assess the senescence-related changes in cauliflower during postharvest storage. In this study, fresh cauliflower curds were treated with 6-benzylaminopurine (BAP) at three concentrations (100, 200, or 300 ppm w/v) and its effects on lipid peroxidation, membrane integrity, bioactive molecules, antioxidant activity, soluble sugar, etc. were observed during storage at ambient conditions. BAP profoundly delayed lipid peroxidation and loss of membrane integrity of the tissue, which was associated with the ageing and senescence processes. A positive effect of BAP on maintaining higher bioactive molecules (ascorbic acid and total phenols), antioxidant activity, and soluble sugar was also observed, which was decreased in control curds. A correlation among different quality parameters was also calculated. The results suggested that the maximum storability period for control curds was 6 days, while BAP treated (200 and 300 ppm) curds could be stored with optimal quality and enhanced antioxidant activity up to 12 days at 25 °C.

Biogenesis of mitochondria in cauliflower (Brassica oleracea var. botrytis) curds subjected to temperature stress and recovery involves regulation of the complexome, respiratory chain activity, organellar translation and ultrastructure

The biogenesis of the cauliflower curd mitochondrial proteome was investigated under cold, heat and the recovery. For the first time, two dimensional fluorescence difference gel electrophoresis was used to study the plant mitochondrial complexome in heat and heat recovery. Particularly, changes in the complex I and complex III subunits and import proteins, and the partial disintegration of matrix complexes were observed. The presence of unassembled subunits of ATP synthase was accompanied by impairment in mitochondrial translation of its subunit. In cold and heat, the transcription profiles of mitochondrial genes were uncorrelated. The in-gel activities of respiratory complexes were particularly affected after stress recovery. Despite a general stability of respiratory chain complexes in heat, functional studies showed that their activity and the ATP synthesis yield were affected. Contrary to cold stress, heat stress resulted in a reduced efficiency of oxidative phosphorylation likely due to changes in alternative oxidase (AOX) activity. Stress and stress recovery differently modulated the protein level and activity of AOX. Heat stress induced an increase in AOX activity and protein level, and AOX1a and AOX1d transcript level, while heat recovery reversed the AOX protein and activity changes. Conversely, cold stress led to a decrease in AOX activity (and protein level), which was reversed after cold recovery. Thus, cauliflower AOX is only induced by heat stress. In heat, contrary to the AOX activity, the activity of rotenone-insensitive internal NADH dehydrogenase was diminished. The relevance of various steps of plant mitochondrial biogenesis to temperature stress response and recovery is discussed.

Potassium Fractions in Soil and Response of Cauliflower (Brassica oleraceavar. Botrytis) in Coarse Textured Soils of Rangareddy District

Coarse textured soils of Rangareddy district were collected from thirty locations and analyzed for potassium (K) fractions. A greenhouse experiment was conducted with the collected soils to know the response of cauliflower to K application. The level of extraction of K by different extractants followed the order: boiling HNO3 (1 M) > NaBPh4 (0.2 M) > citric acid (0.01 M) > NH4OAc (NN) > oxalic acid (0.01 M) > acetic acid (0.01 M). The amount of K extracted by different extractants was more in sandy clay loam soil of Mominpet and very low in sandy soils of Emamguda. The NH4OAc extracted an amount of 54.2 to 242.3 mg kg-1 with an average of 130.3 mg kg-1 and it showed highly significant correlation with 0.2 M NaBPh4 extractable K (r = 0.926**), plant K uptake (r = 0.931**) and also with curd yield (r = 0.975**) of cauliflower. The mean K uptake in the soils ranged from 0.65 g plant-1 on Emamguda soils to 1.67 g plant-1 on Mominpet soil. Mean curd yield was 352.4 g plant-1 in the control which showed a significant increase to 454.8 g plant-1 with the application of 66.6 mg K2O kg-1 soil. The mean response to the application of K was 25.3 kg cauliflower curd per kg of K applied.

Gibberellin Control of Reproductive Transitions in Brassica oleracea Curd Development

Cauliflower (Brassica oleracea var. botrytis) and broccoli (B. oleracea var. italica) differ in the developmental stage of the reproductive meristem at harvest. A cauliflower head is formed by arrest at the inflorescence meristem stage and broccoli at the flower bud stage, and the horticultural value of the crop depends on synchronous development across the head. In other plant species, gibberellin (GA) can promote floral development and is therefore a candidate for providing the early developmental cues that shape the curd morphology. This research investigated the effect of GAs on the two horticulturally important transitions of the reproductive meristem: initiation of the inflorescence meristem and initiation of floral primordia on the proliferated inflorescence meristems. GA is known to affect the former in many species, but effects on the latter have not been determined. It is also not known whether one or both active forms produced by the two GA biosynthetic pathways is involved in the reproductive transitions in this crop. GAs from the early-13 hydroxylation pathway (GA3) and the non-13 hydroxylation pathway (GA4+7) were applied to the shoot apical meristems of cauliflower and broccoli at three developmental stages: adult-vegetative, curd initiation, and curd enlargement. GAs applied during the adult vegetative stage caused the curd to form faster and after fewer additional nodes in both cauliflower and broccoli. GAs applied to the inflorescence meristem did not cause floral primordia to form nor did the expression of transition-associated genes change. Integrator genes BoLFY and SOC1 had constant expression over 24 hours, and meristem-identity genes BoAP1-a and BoAP1-c remained undetectable. However, GAs applied early during the reproductive phase increased bract development in cauliflower curds. This study shows that GAs from both pathways can trigger the vegetative-to-reproductive transition in both cauliflower and broccoli, resulting in earlier curd formation. However, GAs did not advance the inflorescence-meristem-to-floral-primordium transition; on the contrary, they increased bract incidence in cauliflower, a sign of reversion toward the vegetative stage, suggesting that another pathway is responsible for this second transition in cauliflower and broccoli.

Studies on Effect of Temperature on Curd Yield under Year Round Production System of Cauliflower (Brassica oleraceavar.botrytisL.) under Mid Hills of Himachal Pradesh

The cauliflower early group variety ‘Pusa Himjyoti’, mid group variety ‘Swati’ and late group variety ‘PSB K-1’ were planted at a gap of one month at different planting dates for two consecutive years during 2009–10 and 2010–11 to study the effect of varying temperatures on net curd yield and other associated characters in each maturity group. The varieties varied in their performance for net curd yield as per the maturity group and temperature regime. Early maturing varieties gave high net curd yield under high temperature planting dates whereas mid late and late maturing varieties gave high net curd yield under the mild/low temperature regimes. Curd diameter in early cauliflower was found to be maximum under increasing temperatures whereas mild temperature range helped in producing maximum curd size in mid group variety. Late group variety also produced maximum curd diameter when temperature increased from freezing to 10–15°C. The plant leaf number plant−1 was found to be highest under higher temperatures in all the maturity group varieties. Cauliflower curds irrespective of maturity group took more time to maturity at lower temperatures as compared to the high temperatures for every maturity group and planting date.

Surface decontamination of plant tissue explants with chlorine dioxide gas

The surfaces of plant tissues readily harbor bacteria, fungi, and spores making their preparation and growth by aseptic micropropagation difficult. Recent innovations in chlorine dioxide (ClO2) gas production now allow for the generation of small amounts of the gas to meet specific needs. This report demonstrates the efficacy of ClO2 gas in the preparation of plant tissues for micropropagation. Cauliflower curd was surface decontaminated with 1500, 600, 300, and 150 ppm of gas for 30, 60, 180, and 360 min, and the presence of tissue surfaces for microbiota were assayed. The use of ClO2 gas in this system decontaminated cauliflower curd surfaces at rates equal to bleach treatment, but the ClO2-treated tissues grew more quickly and were healthier than the bleach-treated cauliflower curd samples. Chlorine dioxide gas potentially represents an easy means to surface decontaminate plant tissues intended for micropropagation that, when properly used, does not pose a risk to human health.