This study suggests the yield forecast models for autumn chinese cabbage and radish using crop growth and development information. For this, we construct 24 alternative yield forecast models and compare the predictive power using root mean square percentage errors. The results shows that the predictive power of model including crop growth and development informations is better than model which does not include those informations. But the forecast errors of best forecast models exceeds 5%. Thus it is important to establish reliable data and improve forecast models.

Potassium (K) is an element essential for plant growth. This study was aimed to examine the effects of three formulations of potash feldspar, powder, sand, and granule type on the growth of radish and beet in organic farming. 0.1% three formulations of potash feldspar were treated on the soil before transplanting 15 days-old seedlings of radish and beet in greenhouse. The results showed that all kinds of potash feldspar significantly increased shoot and root growth, and soluble solid contents excepted for root hardness in radish and beet. Among them, the powder type of potash feldspar was the most effective on foliage and root growth of radish and beet. Based on the results, it was confirmed that 0.1% potash feldspar treated in the rhizosphere of radish and beet can promote the growth of them.

Flower bud differentiation by temperature and photoperiod was investigated in early-, medium-, and late-maturing cultivars of radish (Raphanus sativus L.). Flower bud differentiation was induced by only day-length extension treatment (18 hr light/day) in early - and medium-maturing cultivars. Therefore, the early- and medium-maturing cultivars of radish were advanced the time of the flowering by the 2 weeks low temperature duration with day-length extension (18 hr light/day). The vegetative growth of early- and medium-maturing cultivar was the best by only day-length extension (18 hr light/day). However, late-maturing cultivar was needed for the flower bud differentiation and optimal vegetative growth not only long-day but also low temperature during 4~6 weeks at least. Our results suggest the optimal condition for flower bud differentiation in the each early-, medium-, and late-maturing cultivars of radish, which will be useful to develop breeding materials of radish.

This study was conducted to determine the effects of organic fertilization rates on the nutrient accumulation and recovery in radish (Raphanus sativus L.) as well as growth and yield of radish in Jeju island. An understanding the relationships between organic fertilization rate, crop nutrient recovery and crop yield can assist in making organic fertilizer recommendation which balances crop value and environmental risk in organic cultivation. Nitrogen (T-N), phosphate (P2O5) and potassium (K2O) were applied at 0, 115-35-40, 230-70-80 (standard application rate), 460-140-160, 230-200-100 (recommended application rate) and 158-53-35 kg/ha (customary application rate), respectively as the broadcast application of mixed organic fertilizer (N 4.5% - P2O5 1.5% - K2O 1%) in combination with langbeinite (K2O 22%), 100% at sowing period. The organic fertilizer was made of organic materials like oil cakes. Total yield of radish, as fresh weight of roots, increased with increasing organic fertilizer doses to a maximum at rate of standard or soil-testing application. Nitrogen, phosphate and potassium accumulations of radish increased curvilinearly with increasing organic fertilization rate to a maximum at rate of N 460 - P2O5 140 - K2O 160 kg/ha. However, nitrogen, phosphate and potassium use efficiency of applied organic fertilizer decreased curvilinearly or linearly with increasing organic fertilization rate. Application of organic fertilizer in combination with langbeinite (as a potassium source) had significant effect on the yield of radish. Organic fertilization on a basis of standard or soil-testingapplication rate is recommended for maximun radish yield in organic cultivation.

Radish is one of the most widely consumed vegetable crops in Korea. Root is the major part of radish supplied to the market, thus the size, shape, and quality of radish roots are main targets of breeding programs. Despite of the importance of this crop, the molecular breeding of radish is still in the rudimentary stage. In Golden Seed Project, we aim to establish the molecular breeding program of radish using genome-wide approaches. To this end, we selected inbred lines that have distinctive root traits such as yield, shape, disease resistance, and texture. Single nucleotide variation (SNV) among these lines will be identified based on the low coverage genome sequencing data. These SNVs can be used for finding genomic regions associated with root traits from segregating mapping populations which are also in the middle of development. Korean radish roots are harvested after being grown for only nine weeks. During that period, root biomass reaches to more than two kilograms. While investigating the root growth of radish inbred lines, we found that cytokinin contributes as a key growth regulator that promotes radial growth of radish roots. A difference in growth rates of two distinctive inbred lines was explained by the difference in response to cytokinin. Genes responsive to cytokinin are highly enriched in the cambium, the meristematic cell population that drives radial growth. For comprehensive understanding of genes that affect yields of radish roots, we turned to developing a tissue specific transcriptome data using laser capture microdissection. We expect that the compendium of genomics-based data will help establishing molecular breeding of radish at a fast track.

Radish, Raphanus sativus(2n = 18), belonging to the brassicaceae family, is herbaceous plant with 1-2 years life cycle. It is cultivated worldwide for producing leafy and root vegetables. Although an economically important crop, the genetics of yield and quality traits, disease resistance are not well-studies. The major purpose of this project is development of molecular breeding technology in radish. In this project, quantitative trait loci (QTL) for Fusarium wilt resistance of radish were analyzed. To identify QTL, genetic linkage map of radish was constructed using F2 mapping population derived from a cross between two inbred lines, “DB01” (resistant) and “DB05” (susceptible). A total 319 markers have been mapped into nine linkage groups, covering 639.3cM with an average distance of 2cM between loci. QTL mapping detected 2 loci conferring Fusarium wilt resistance. Two QTLs were located on LG3 and LG7, respectively. The QTL of LG3, flanked by EAGGMCT6 and WALK500 marker, exhibited a LOD value ranging from 2.3 to 8.7, and the R2 (Phenotypic variations) ranging from 28 to 48% in four tests. This QTL was named qYR1. The QTL of LG7, flanked by EACCMCAC-202 and DCJ14-390 marker, exhibited a LOD value ranging from 6.2 to 10.6, and the R2 ranging from 42 to 55% in four tests. This QTL was named qYR2. The results of the QTL analysis may be useful in marker-assisted selection (MAS) of Fusarium wilt resistant radish cultivars.

십자화과 작물에서 SRK와 SP11 유전자는 자가불화합 반응을 매개하는 주요 유전자이다. 무(radish)에서 S-locus haplotype을 분류 및 확인하기 위한 첫 단계로, SRK와 SP11유전자의 온전한 서열확보를 위해 기존 연구를 통해 밝혀진 Brassica rapa의 SRK유전자 서열을 활용해 local blast를수행했다. 이를 통해 무 draft genome sequence에서 SRK유전자와 높은 상동성이 있는 15개의 후보유전자들을 찾았다. 이후 B. rapa genome data를 활용한synteny analysis를 통해 무 draft genome sequence에서 B.rapa의 S-locus region과 synteny를 가지는 scaffold를 R7 연관그룹에서 확인했다. 해당 scaffold에서 SRK와 SLG 유전자의 서열을 확보할 수 있었다. 이렇게 확보한 SRK유전자서열의 정보를 통해 NCBI database에서 동일한 유전자서열을 찾을 수 있었고, 해당 논문에서 연구된 같은 haplotype의 SP11유전자서열을local blast의query로 사용해서 무 draft genome sequence에서 SP11 유전자정보가 포함된 scaffold를 찾을 수 있었다. 이로써, SRK, SLG, SP11/SCR 유전자를 포함하는 53,785bp, 42,804bp, 10,165bp 크기의 온전한 genomic 서열을 확보하게 되었다. 무 S locus haplotype을 분류하기 위한 체계를 만들기 위해 S-locus core region에 있는 SLL2유전자를 활용했다. SRK 유전자의 경우, 무 genome내에 상동성이 높은 homologous gene을 가지고 있고, SP11유전자의 경우는 exon지역의 다형성이 너무 높아PCR기반의 marker개발이 어렵기 때문에 SLL2유전자를 활용했다. 가지고 있는 다양한 무 육종계통에서 SLL2 유전자에 특이적인 primer set을 사용해 SLL2유전자를 증폭시킨 뒤, sequencing하여 SLL2유전자에 대한 다양한 대립유전자들의 서열을 확보할 수 있었다. 확보한 SLL2대립유전자 서열을 비교함으로써 S locus haplotype분류체계를 만드는데 활용 가능한 conserved region을 exon2와 exon6에서 확인할 수 있었고, 해당 부분에 design된 primer를 통해 다양한 무 육종계통에서 단일한 PCR band를 확인할 수 있었다. 이는 직접적인 sequencing을 통해 S locus haplotype을 식별하는데 충분한 정보를 제공함으로써 무 육종에 큰 도움이 될 것이라 생각된다.

Anthocyanins, providing the bright red-orange to blue-violet colors, flavonoid-derived pigments with strong antioxidant activity that have benefits for human health. We isolated RsMYB1, which encodes an R2R3 MYB transcription factor (TF), from red radish plants (Raphanus sativus L.) that accumulate high levels of anthocyanins. RsMYB1 shows higher expression in red radish than in common white radish, in both leaves and roots, at different growth stages. regulatory genes. Transient expression of RsMYB1 in tobacco showed that RsMYB1 is a positive regulator of anthocyanin production. Also, the synergistic effect of RsMYB1 with B-Peru was larger than the effect of Arabidopsis plants stably expressing RsMYB1 produced red pigmentation throughout the plant, accompanied by up-regulation of the six structural and two regulatory genes for anthocyanin production. This broad transcriptional activation of anthocyanin biosynthetic machinery in Arabidopsis included up-regulation of TRANSPARENT TESTA 8, which encodes a bHLH-type TF. These results suggest that overexpression of RsMYB1 promotes anthocyanin production by triggering the expression of endogenous bHLH genes as potential binding partners for RsMYB1. In addition, RsMYB1-overexpressing Arabidopsis plants had a higher antioxidant capacity than did non-transgenic control plants. Taken together, RsMYB1 is an actively positive regulator for anthocyanins biosynthesis in radish plants and it might be one of the best targets for anthocyanin production by single gene manipulation being applicable in diverse plant species.

To develop molecular markers for late flowering time in radish we performed QTL-seq analysis in which whole genomes are sequenced and SNPs between two groups showing opposite phenotypes in F2 population are analyzed to find regions or QTLs involved in a trait of interest. Two inbred lines (NH-JS1 and NH-JS2) showing opposite phenotypes of flowering time were selected to generate F2 population for the analysis. NH-JS1 showed late flowering time whereas NH-JS2 early flowering time. Genomic DNA from the two lines were extracted and sequenced. In addition F2 population from F1 between NH-JS1 and NH-JS2 was generated and flowering time phenotypes of 180 F2 plants were analyzed. We selected 11 plants with late flowering time and 12 plants showing early flowering time. We extracted DNA from each individuals from the two groups and bulked them to generate two bulked DNA samples that are subject to whole genome resequencing. Preliminary analysis of SNP data from the resequencing showed that there may be several QTLs involved in flowering time control in radish.

Radish (Raphanus sativus L.) is a widely-consumed root vegetable that is grown worldwide. To utilize the radish genetic resources for breeding research, we collected radish germplasms and evaluated their morphological and genetical characteristics. Here, phylogenetic relationship of 288 accessions were analyzed using 16 SSR markers and classified cytoplasm male sterility (CMS) types using cpDNA-based molecular markers. To create a collection of 288 accessions, 188 and 73 accessions were selected from RDA-Genebank (Korea) and NIAS-Genebank (Japan), respectively, after generation advancement for the accessions with low uniformity. In addition, 27 elite lines currently used for commercial radish breeding programs were included. In the result of phylogenetic analysis, 288 accessions were clustered into 5 major groups corresponding to the morphological traits and origins at the similarity coefficient value of 0.51. Analysis of CMS types revealed that majority of accessions were determined as DBRMF1 and DBRMF2 mitotypes, 15 accessions to Ogura and 4 accessions to DCGMS mitotypes. Further genetic analysis for radish germplasm will be valuable in assisting radish f1 hybrid breeding.

Fusarium wilt (FW), caused by the soil-borne fungal pathogen Fusarium oxysporum is a serious disease in cruciferous plants, including the radish (Raphanus sativus). To identify quantitative trait loci (QTL) or gene(s) conferring resistance to FW, we constructed a genetic map of R. sativus using an F2 mapping population derived by crossing the inbred lines ‘835’ (susceptible) and ‘B2’ (resistant). A total of 220 markers distributed in 9 linkage groups (LGs) were mapped in the Raphanus genome, covering a distance of 1041.5 cM with an average distance between adjacent markers of 4.7 cM. Comparative analysis of the R. sativus genome with that of Arabidopsis thaliana and Brassica rapa revealed 21 and 22 conserved syntenic regions, respectively. QTL mapping detected a total of 8 loci conferring FW resistance that were distributed on 4 LGs, namely, 2, 3, 6, and 7 of the Raphanus genome. Of the detected QTL, 3 QTLs (2 on LG 3 and 1 on LG 7) were constitutively detected throughout the 2-years experiment. QTL analysis of LG 3, flanked by ACMP0609 and cnu_mBRPGM0085, showed a comparatively higher logarithm of the odds (LOD) value and percentage of phenotypic variation. Synteny analysis using the linked markers to this QTL showed homology to A. thaliana chromosome 3, which contains disease-resistance gene clusters, suggesting conservation of resistance genes between them.

염화칼슘 농도를 달리한 쌈무의 조직감 개선 효과, 물리·화학적 특성 및 관능평가를 비교하였다. 염화칼슘 첨가 후 저장 전 쌈무들의 pH와 총산도 범위는 각각 약 3.8~4.0와 2.7~3.0(%, w/v)이었으며, 28일 동안의 저장기간 동안 저장 온도 4℃와 50℃의 시료들은 저장 전 초기 pH와 총산도의 범위를 유지하였다. 그러나 저장온도 25℃에서 쌈무 시료들은 저장 전 초기 pH 범위보다 0.5가 낮아졌고 총산도는 1.9~2.2(%, w/v)가 증가되어졌다. 염화칼슘의 첨가에 따른 쌈무 시료들의 색도를 측정한 결과, 28일 저장동안 4℃에서 저장된 쌈무 시료들은 현저한 차이를 나타내었으나(△E값 1.66~8.21) 50℃에서 저장된 시료들은 다른 계통의 색으로(△E값 23~27) 큰 변화를 보였다. 쌈무 시료들의 경도에 있어서, 저장온도 4℃와 25℃에서 28일 동안 저장된 쌈무 시료들의 경도는 저장 전 쌈무 시료들의 경도와 큰 차이를 보이지 않았고, 50℃에서는 염화칼슘 처리량이 증가 할수록 경도가 높게 유지되고 있음을 확인 할 수 있었다. 쌈무 시료들의 씹힘성에 있어서는 전반적으로 경도의 결과와 유사한 경향을 보였다. 이로써 염화칼슘처리로 쌈무의 조직감을 향상시킬 수 있음을 확인하였다. 4℃에서 28일 동안 저장된 쌈무 시료들의 관능평가 결과, 0.4% 염화칼슘이 첨가된 쌈무 시료가 맛, 경도와 전반적인 기호도에서 가장 높은 점수를 받아 유통 저장기간 동안 관능품질을 유지하면서 쌈무의 조직감을 유지시킬 수 있는 염화칼슘 첨가량이라 판단된다.

본 연구는 국내에서 생산·유통되는 무 새싹채소의 미생물 및 영양학적 품질지표를 조사하기 위하여 2개월에 한번씩 무 새싹채소를 구매한 후, 미생물 오염도, 총 페놀함량,총 카로티노이드 함량, 총 글루코시놀레이트 함량 및 개별 글루코시놀레이트 화합물을 분석하고, 항산화활성을 측정해보았다. 일반세균수와 대장균군수는 평균 7.45±0.73 log CFU/g과 6.55±0.61 log CFU/g을 나타내었으며, 겨울철에는 각각 6.70±0.61 log CFU/g과 6.09±0.50 log CFU/g으로 낮았고, 여름철에는 각각 7.91±0.15 log CFU/g과 6.94±0.17log CFU/g으로 높은 오염도를 나타내었다. 총 페놀함량은 평균 16.82±0.69 mg/g을 나타내었으며 구매시기별 유의차는 없는 것으로 확인되었다. 총 카로티노이드 함량은 평균값이 10.73±2.08 mg/g로, 계절별로 비교했을 때 겨울이 여름보다 높은 함량을 나타내었다. 총 글루코시놀레이트 함량은 평균 65.80±12.68 mg/g이었으며, 12월에 73.47±4.67mg/g으로 가장 높은 함량을 보였으나, 구매시기에 따른 유의적인 차이는 나타나지 않았다. 개별 글루코시놀레이트함량은 glucoerucin, glucoraphenin, gluconasrutiin, glucobrassicin의 순서로 높게 나타내었으며, glucoerucin을 제외한 성분들은 구매시기에 따른 성분함량에서 유의적 차이를 나타내지는 않았다. 항산화 활성은 DPPH 라디컬 소거능으로 측정하였는데, 2월에 가장 높고 6월에 가장 낮은 항산화 활성을 보여, 겨울철이 여름철에 비해 항산화활성이 높은 것을 알 수 있었다. 따라서, 무 새싹채소의 미생물 오염도, 총 카로티노이드 함량 및 항산화 활성은 구매시기에 따라 함량 및 활성의 변화를 보였으나, 총 페놀 함량, 총 글루코시놀레이트는 구매시기별 유의적인 차이 없음을 확인할 수 있었다.

본 연구는 환경 친화적인 새싹채소류의 고품질화를 위한 경제적이고 효율적인 살균기술을 개발할 목적으로 국내산 적무 종자의 다양한 열처리 방법에 따른 발아율과 미생물 저감효과를 조사하였다. 열수처리는 60, 65, 70, 75, 80, 90℃에서 각각 30, 60초간 실시하였고, 건열처리는 70, 80, 90, 100℃에서 5분간 실시하였다. 열수 처리에 따른 미생물의 제어효과는 시간에 따른 유의적인 차이는 보이지 않았으나, 온도변화에 따른 유의적인 차이를 나타내었다 (p<0.001). 70℃ 이상의 온도에서 총세균수는 3 logs 이상의 감소를 보였으며, L. monocytogenes는 검출되지 않았다. 건열처리는 온도변화에 따른 유의적인 차이를 나타내었다 (p<0.001). 100℃에서 5분간 처리한 후 총세균과 L.monocytogenes 수는 3 logs 이하 감소하였다. 열수처리에 따른 발아율의 변화는 처리 전과 후 모두 시간에 따른 유의적인 차이는 보이지 않았으나, 75℃ 이상의 온도에서 온도증가에 따라 유의적으로 감소하였다(p<0.001). 한편, 열수처리 후 침지시킨 종자에서 발아가 더 촉진되는 것으로 나타났다. 건열처리에 따른 발아율은 80℃ 이상의 온도에서 온도 증가에 따라 유의적으로 감소하였다(p<0.001). 건열처리한 후 증류수에 3시간 침지시킨 종자의 발아율은 90℃ 이상의 온도에서 유의적으로 감소하였다(p<0.05). 결론적으로 적절한 열처리는 75℃, 30분 이상의 열수처리하는 방법으로, 적무 새싹채소의 종자의 미생물학적 안전성을증가시킴과동시에발아율을증가시키는것으로판단된다.

A root serves as an essential organ in plant growth by up-taking nutrients and water from soil and supporting the rest of a plant body. Root apical growth and system architecture have been extensively studied because they strongly affect overall plant growth and yields. Some plant species also utilize roots as storage organs. Many of them, including sweet potatoes (Ipomoea batatas), cassava (Manihot esculenta), and radish (Raphanus sativus) are important crops, however their root development has remained elusive. In this study, we characterized radial root growth in the radish and found that it is very similar to the secondary growth in stems. We identified well established cambium zones in the actively growing radish roots. Cell proliferation activities in the cambium zones positively correlated with root growth rates and final yields. Through a comparative analysis with Arabidopsis root expression data, we selected some putative transcription factors whose expression is highly enriched in the cambia and validated their expression in various stages of radish roots. By comparing their expression in two inbred lines with distinctive radial root growth, we identified transcription factors that are involved in morphological differences. More importantly, our investigation suggests that the differences in the root growth of two radish inbred lines are from changes in cytokinin responses. These findings together highlight that radish could serve as an excellent system for studying root crops and that transcriptional regulation and cytokinin signaling are indispensable for the secondary root growth.

Glucosinolates (GLS) are secondary metabolites commonly occurring in Brassica crops and more than 130 different GLS have been reported in diverse plants. Recent studies have indicated that isothiocyanate (ITC) derived from GLS by hydrolysis had a potential for anticancer activity against several rumor cells on human. In addition, it was found that glucoraphenin (GRE) and glucoraphasatin (GRH) were abundant and differently regulated in radish plant, depending upon organs and developmental stages. Microspores isolated from flower buds of radish were cultured in vitro to obtain doubled haploid (DH; but homozygous) lines in a short time period. The present study was conducted to determine the concentration of GRE and GRH, an immediate precursor of ITC from DH lines of radish plant. Total 41 DH lines were selected based on flow cytometry analysis. The seeds, obtained by bud pollination from the DH lines, were planted and 3-weeks-old young seedlings were used for the major aliphatic GLS analysis. Amounts of GRH were highly variable from the DH lines ranging from 2.3 to 31.5 mg·g-1 dry weight (DW). The donor plant (DP) contained 18.4 mg·g-1 DW. It was noticed that there were 6-fold differences in the amounts of GRE between the highest and lowest DH lines. Among 41 lines tested, 14 DH lines of radish plant were significantly reduced in the amount of sum of GRH and GRE compared those of the donor plant (P<0.05), whereas only three lines increased. The results obtained in the present study will lend to select genotypes with low and high GLS contents of radish plant. In addition, those DH lines will aid to elucidate a biosynthetic pathway of the aliphatic GLS in radish plant, which remain for the most part unsolved.

Anthocyanins are very important constituent of human diet. In recent years, they have gained much attention due to their antioxidative properties. As the radish (Raphanus sativus L) has rich content of anthocyanins, the study is aimed to develop increased functional radish from selected radish varieties. ‘Bordeux’ is a hybrid variety of breeding between one accession derived from ‘Oharu’ as a maternal variety and ‘Chungpihongsim’ as a paternal variety. In this study, we investigated the new varieties of radish commonly consumed in Republic of Korea for their total phenolic content (TPC) and antioxidant activities using three (DDPH, FRAP and CUPRAC) different assays. The selected radish varieties like ‘Bordeux’, ‘Chungbok’, ‘3209’, ‘Chungwoon’, ‘Oharu’, and ‘Chungpihongsim’ were procured from the company Syngenta Korea. Among the selected radish varieties, ‘Bordeux’ (289 μg/g FW) and ‘Chungpihongsim’ (276 μg/g FW) revealed maximum amount of phenolics; whereas ‘3209’ (103 μg/g FW) and ‘Chungwoon’ (166 μg/g FW) showed the lower amount of phenolics content, respectively. Extracts from these studied radishes showed good to moderate antioxidant activities. The varieties ‘Chungpihongsim’ and ‘Bordeux’ revealed maximum antioxidant activity for all assays as demonstrated. However, some varieties like ‘3209’ and ‘Oharu’ exhibited the lowest antioxidant activity in all the tested assays, viz; DPH, FRAP and CUPRAC in μg TE/g FW, respectively. The antioxidant activities may be attributed to the higher phenolic acid contents as a linear relation was observed between the two components and the antioxidant parameters.

In order to raise awareness about environmental protection, people are paying more attention now-a-days in reusing wastepaper. As a result, most countries in the world have already made significant progress related to wastepaper recycling technology. The aim of this study was to investigate the effects of slow-release nitrogen fertilizer (SRNF) on the growth of radish plants. Wastepaper was deinked by alkaline solution and SRNF was produced from fertilizer impregnated wastepaper, which applied to an experimental plot compared with a urea fertilized plot. The plant height and total chlorophyll content of the radishes were higher while they were treated with SRNF than with urea. Some agronomic and chemical components were also observed and significant differences between the two fertilizers were found. When the soil was treated with SRNF, the pH, organic matter and total nitrogen content were higher than in the soil which was treated with urea.

In this study, the effects of the use of a starter on radish soaked at 4℃ for 28 days using two kinds of domestic sun-dried salt (white and gray salt) were determined. As a result, the moisture contents of the radish soaked with white and gray salt were 7.93 and 4.50%, respectively. The salinity levels were found to be equal (90%). No significant difference was found between the two groups in terms of the mineral contents of the salts therein (37812.41±1922.95 and 39755.13±1205.70 mg/100 g, respectively). However, iron and zinc contents of gray salt were higher than those of white salt while the calcium, potassium, and magnesium contents were lower than those of white salt. After the addition of the starter, the sugar content increased, the pH decreased, and the total acidity rapidly decreased compared with the non-starter group during fermentation. The total microorganism count of the two groups increased during the fermentation period of 28 days. From the initial fermentation for 7 days, the lactic acid bacteria in the non-starter group increased while those in the leuconostoc starter group steadily increased within the whole fermentation period. The Leuconostoc spp. in non-starter group increased, but that in the starter group decreased to pH 4.0 on day 14.