Mapping QTLs that control the performance of rice tissue culture and evaluation of derived near-isogenic lines

Quantitative trait loci (QTLs) that control the performance of tissue culture in rice were detected by using 116 RFLP markers and 183 BC₁F₃ lines derived from two varieties, Koshihikari and Kasalath. With time, the seed callus of Koshihikari tends to turn brown and stop growing, while that of Kasalath remains yellowish-white and proliferates continuously. The performance of tissue culture in the induction of calli from seed, the subculture of induced calli, and shoot regeneration were evaluated by five indices: induced-callus weight, induced-callus color, subcultured-callus volume, subcultured-callus color, and regeneration rate. Through callus induction and subculture, eight putative QTLs (P < 0.001) were located on chromosomes 1, 4, and 9. Among these QTLs, five Kasalath alleles and three Koshihikari alleles improved tissue culture performance. No QTL for regeneration was found. Among all the QTLs, qSv1 explained the largest phenotypic variance, 33%, in subcultured-callus volume. In induced-callus color, two detected QTLs accounted for 36.4% of the total phenotypic variance; this was the highest score among the five indices used to evaluate the performance of tissue culture. Three near-isogenic lines for QTLs, located in two regions on chromosome 1, were developed to evaluate their tissue culture performance. The Kasalath alleles in qSv1 and qSc1-1 improved callus color through callus induction and subculture, and increased the subcultured-callus volume and the fresh weight of regenerated calli, including shoots, roots, and differentiated structures. In qSc1-2, the Kasalath allele improved callus color through induction and subculture. These results verified the presence of QTLs for the volume and color of subcultured callus on chromosome 1, qSv1, qSc1-1, and qSc1-2.     

Mapping QTLs for tissue culture response of mature wheat embryos

The mature wheat embryo is arguably one of the best explants for genetic transformation because of its unlimited availability and lack of growth season restriction. However, an efficient regeneration system using mature wheat embryos (Triticum aestivum L.) is still not available. To identify genes related to the tissue culture response (TCR) of wheat, QTLs for callus induction from mature embryos and callus regeneration were mapped using an RIL population derived from the cross of "Wangshuibai" with "Nanda2419" which has a good TCR. By whole genome scanning we identified five, four and four chromosome regions conditioning, respectively, percent embryos forming a callus (PEFC), percent calli regenerating plantlets (PCRP), and number of plantlets per regenerating callus (NPRC). The major QTLs QPefc.nau-2A and QPcrp.nau-2A were mapped to the long arm of chromosome 2A, explaining up to 22.8% and 17.6% of the respective phenotypic variance. Moreover, two major QTLs for NPRC were detected on chromosomes 2D and 5D; these together explained 51.6% of the phenotypic variance. We found that chromosomes 2A, 2D, 5A, 5B and 5D were associated via different intervals with at least two of the three TCR indexes used. Based on this study and other reports, the TCRs of different explant types of wheat may be under the control of shared or tightly linked genes, while different genes or gene combinations may govern the stages from callus induction to plantlet regeneration. The importance of group 2 and 5 chromosomes in controlling the TCRs of Triticeae crops and the likely conservation of the corresponding genes in cereals are discussed.     

Mapping quantitative trait loci for tissue culture response in VCS3M-DH population of Brassica rapa

Key message

Quantitative trait loci (QTL) controlling callus induction and plant regeneration were identified in the VCS3M-DH population of Brassica rapa.

Abstract

Quantitative trait loci (QTL) controlling callus induction and plant regeneration were identified in the VCS3M-DH population of Brassica rapa. The VCS3M-DH population showed wide and continuous variation in callus induction and shoot regeneration. Significant coefficient correlations were detected between these two parameters. Broad-sense heritability (h ²) for the two traits was around 0.7, indicating genetic regulation of regeneration ability in this population. In the composite interval mapping analysis, two QTLs for callus induction ability, qCi2 and qCi7, were mapped on chromosome A02 and A07, explaining 28.6 % of phenotypic variation. For plant regeneration, four QTLs, qPr6-1 qPr6-2, qPr7, and qPr9 were identified on chromosome A06, A07, and A09, which in total explained 50.1 % of phenotypic variation. Furthermore, 15 putative candidate genes were found on the interval of the six QTLs, which were related to various plant hormones, MADS-box genes, and serine/threonine related genes. These results provide important information to identify genes related to tissue culture ability in B. rapa.     

Quantitative trait loci associated with androgenic responsiveness in triticale (×Triticosecale Wittm.) anther culture

Quantitative trait loci (QTLs) associated with androgenic responsiveness in triticale were analyzed using a population of 90 DH lines derived from the F1 cross between inbred line ‘Saka 3006’ and cv. ‘Modus’, which was used in a number of earlier studies on molecular mapping in this crop. Using Windows QTL Cartographer and MapQTL 5.0, composite interval mapping (CIM) and association studies (Kruskal–Wallis test; K–W) for five androgenesis parameters (androgenic embryo induction, total regeneration and green plant regeneration ability, and two characteristics describing final androgenesis efficiency) were conducted. For the studied components of androgenic response, CIM detected in total 28 QTLs which were localized on 5 chromosomes from A and R genomes. Effects of all QTLs that were identified at 2.0 or above of the LOD score explained 5.1–21.7?% of the phenotypic variation. Androgenesis induction was associated with seven QTLs (LOD between 2.0 and 5.8) detected on chromosomes 5A, 4R, 5R and 7R, all of them confirmed by K–W test as regions containing the markers significantly linked to the studied trait. What is more, K–W test revealed additional markers on chromosomes: 5A, 2BL, 7B and 5R. Both total and green regeneration ability were controlled by genes localized on chromosome 4A. Some of the QTLs that affected final androgenesis efficiency were identical with those associated with androgenic embryo induction efficiency, suggesting that the observed correlation may be either due to tight linkage or to pleiotropy. Key message Five regions of the triticale genome were indicated as revealing significant marker/trait association. Markers located in these regions are potentially useful for triticale breeding through marker-assisted selection.     

不同遗传背景及环境中水稻（Oryza sativa L.）穗长的QTLs和上位性分析

以粳稻Ａｚｕｃｅｎａ为父本与灿稻ＩＲ６４杂交发展的一双单倍体（ＤＨ） 本,与灿稻ＩＲ１５５２杂交发展的一重组自交系（ＲＩ）群体为材料,应用分子标记图说对２个群体在大田答舅栽２个环境下的穗长进行ＱＴＬｓ及上位性效应分析,ＤＨ群体中共检测６个穗长ＱＴＬｓ,位于第１、４长染色体上的３个ＱＴＬｓ,,在２个环境中稳定表达,未检测一闰性效应,加性效应为穗长遗传主效应,ＲＩ群体中,共检测到３个穗长ＱＴＬｓ及６对     

水稻花药培养力的遗传分析及基因定位

在栽培稻的籼粳亚种间,花药培养力存在显著差异,这一差异主要是由遗传因素引起的。以适合籼粳稻杂种花药培养的SK_3培养基,经花药培养获得了一个籼粳交F_1代的加倍单倍体(DH)群体,对该群体的110个株系用同一种培养基进行花药培养,利用该群体构建的分子图谱进行有关水稻花药培养力的数量性状基因座位(QTLs)的分析。结果表明,与水稻花药培养力有关的4个性状在DH群体中均表现为连续分布,愈伤组织诱导率与绿苗分化率之间不存在相关性,而绿苗产率与愈伤组织诱导率和绿苗分化率均显著相关。在第6、7、8、10和12 5条染色体上分别检测到与愈伤组织诱导率有关的5个QTLs,其加性效应均为正。在第1和第9染色体上检测到与绿苗分化率有关的2个QTLs,这两个性状间的QTs不存在连锁。在第9染色体上有一个主效基因与白苗分化率有关,对绿苗产率则没有检测到特有的QTL。     

Marker-assisted selection for identification of plant regeneration ability of seed-derived calli in rice (Oryza sativa L.)

Quantitative trait loci (QTL), associated with the ability of plant regeneration from seed-derived callus of rice, were mapped using a recombinant inbred (RI) population from Milyang 23/Gihobyeo. Each flanking marker, RZ474 and RZ575, tightly linked to two QTLs (qSGR-3-1 and qSGR-3-2) that are located on chromosome 3 was used in marker-assisted selection (MAS). These markers were tested on IR 36/MG RI036 (F3), Milyang 23/MG RI036 (F3), and forty-one rice cultivars. A restriction fragment length polymorphism (RFLP) marker, RZ575, that is located on chromosome 3 could effectively differentiate lines with high and poor regeneration ability, based on marker genotypes. This marker might be applicable for screening rice germplasms with high regeneration ability. Its introgression into elite lines might also be valuable in breeding programs to develop highly responsive genotypes to tissue culture.     

Plant regeneration from in vitro cultures of anthers and mature seeds of rice (Oryza sativa L.) cv. Basmati-370

Pollen plants were obtained from anther-derived calli of the indica rice variety Basmati-370. Anther-response (anthers producing pollen derived calli) and plant regeneration frequency from the pollen derived calli. was very low. Donor plants which flowered at the average max/min. temperature of 34.2°/23.3°C gave a significantly higher anther-response to in vitro techniques, than did those which flowered at 29.1°/16.4°C. Somatic callus induction and subsequent plant regeneration was readily obtained from mature seed embryos. While 2,4-D or 2,4,5-T (1 or 2 mg/l) proved highly efficient for callus induction, tryptophan (50 or 100 mg/l) induced a high frequency of green plants from the calli.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - 2,4,5-T 2,4,5-trichlorophenoxyacetic acid - NAA naphthaleneacetic acid - IAA indoleacetic acid - K kinetin - BA benzyladenine - Trp tryptophan - CW coconut water     

The effect of rye chromosomes on callus induction and regeneration in callus cultures of immature embryos of wheat-rye substitution lines, Triticum aestivum L. cultivar Saratovskaia 29/Secale cereale L. cultivar Onokhoiskaia

The effect of individual rye chromosomes on the induction of callus and the character of its regenerating capacity was studied with cultured immature embryos of wheat-rye (Triticum aestivum L. cv. Saratovskaya 29-Secale cereale L. cv. Onokhoiskaya) substitution lines. The genotypic diversity of the substitution lines proved to significantly affect variation of parameters characterizing the major types of callus cultures, that is, frequencies of embryogenic calli, which are capable of shoot regeneration, and of morphogenic calli, which produce root structures. Functioning in the genotypic background of common wheat cultivar Saratovskaya, chromosomes 2R and 3R of rye cultivar Onokhoiskaya stimulated significantly the induction of embryogenic callus highly capable of shoot regeneration. Rye chromosome 2R present in place of chromosome 2D in the common wheat genome suppressed the induction of callus producing root structures. Rye chromosomes 1R and 6R suppressed the induction of embryogenic callus capable of shoot regeneration.     

Mapping quantitative trait loci controlling seed longevity in rice ( Oryza sativa L.)

Quantitative trait loci (QTLs) controlling seed longevity in rice were identified using 98 backcross inbred lines (BILs) derived from a cross between a japonica variety Nipponbare and an indica variety Kasalath. Seeds of each BIL were kept for 12 months at 30 degrees C in dry conditions to promote loss of viability. To measure seed longevity, we performed an additional aging-processing treatment for 2 months at 30 degrees C maintaining seeds at 15% moisture content. We measured the germination percent of these treated seeds at 25 degrees C for 7 days as the degree of seed longevity. The germination of BILs ranged from 0 to 100% with continuous variation. Three putative QTLs for seed longevity, qLG-2, qLG-4 and qLG-9, were detected on chromosome 2, 4 and 9, respectively. Kasalath alleles increased the seed longevity at these QTLs. The QTL with the largest effect, qLG-9, explained 59.5% of total phenotypic variation in BILs. The other two QTLs, qLG-2 and qLG-4, explained 13.4 and 11.6% of the total phenotypic variation, respectively. We also verified the effect of the Kasalath allele of qLG-9 using chromosome segment substitution lines. Furthermore, QTLs for seed dormancy were identified on chromosomes 1, 3, 5, 7 and 11. Based on the comparison of the chromosomal location of QTLs for seed longevity and seed dormancy, these traits seem to be controlled by different genetic factors.     

Application of activated charcoal and nanocarbon to callus induction and plant regeneration in aromatic rice (Oryza sativa L.)

The investigations of nanotechnology with the application on agricultural products also have been few reported, especially the plant regeneration. The effects of activated charcoal and nanocarbon on the callus induction and plant regeneration of aromatic rice were studied. Activated charcoal was added into the callus induction and regeneration medium. The presence of activated charcoal in the callus induction medium (100–500 mg L^?1), activated charcoal significantly reduced the percentage of the callus induction and biomass accumulation (fresh weight, dry weight and size). Whereas, the regeneration medium supplemented with 100 mg L^?1 of activated charcoal showed the highest percentage of plant regeneration (61.90%) and the ratio of the number of seedlings to the number of regenerated calli (RSR; 3.06) that derived from the callus induction medium (without activated charcoal). Moreover, the induced calli derived from the callus induction medium supplemented with nanocarbon at 5 mg L^?1 showed the highest percentage of callus induction (94.70%), the percentage of green spots (95.83%), the percentage of plant regeneration (60.42%) and the RSR (3.12) when transferred the calli into the regeneration medium (without nanocarbon). After that, nanocarbon was also added into the regeneration medium. The percentage of green spots (96.08%), the percentage of plant regeneration (62.75%) and the RSR (3.16) obtained from the regeneration medium supplemented with 20 mg L^?1 of nanocarbon showed the highest values. This experiment showed that the optimum concentration of activated charcoal and nanocarbon had potential to enhance the callus induction and plant regeneration frequencies in tissue culture medium of aromatic rice.     

Genetic resolution and verification of quantitative trait loci for flowering and plant height with recombinant inbred lines of maize.

Recombinant inbred (RI) lines offer several advantages for detecting quantitative trait loci (QTLs), including increased precision of trait measurements, power for detection of additive effects, and resolution of linked QTLs. This study was conducted to detect and characterize QTLs in maize for flowering and plant height and to compare QTL detection in an early (F2:3) generation of the same population. One hundred and eighty-six RIs from a cross between inbred lines Mo17 and H99 were evaluated in a replicated field experiment and analyzed at 101 loci detected by restriction fragment length polymorphisms. QTLs were identified by single-factor analysis of variance. A total of 59 QTLs were detected for plant height, ear height, top height, anthesis, silk emergence, and anthesis to silk interval. Individual QTLs explained 2.2-15.4% of trait variation, and multiple models including all QTLs detected for a trait explained up to 52.5% of the phenotypic variation. Comparison of QTLs detected with 150 F2:3 lines from the same population indicated that 16 (70%) of the 23 F2:3 QTLs were also observed in the F6:7 generation. Parental effects were consistent across generations. At 14 of the 16 QTLs detected in both generations, genetic effects were smaller in the F6:7. Also, some QTLs detected in the F2:3 were resolved into multiple linked QTLs in the F6:7, indicating the additional power of RI populations for mapping, with important implications for marker-assisted selection as well as map-based cloning of QTLs. Key words : Zea mays, RFLP, plant breeding, genetics, recombination.     

Mapping quantitative trait loci controlling seed dormancy and heading date in rice, Oryza sativa L., using backcross inbred lines

 To detect quantitative trait loci (QTLs) controlling seed dormancy, 98 BC₁F₅ lines (backcross inbred lines) derived from a backcross of Nipponbare (japonica)/Kasalath (indica)//Nipponbare were analyzed genetically. We used 245 RFLP markers to construct a framework linkage map. Five putative QTLs affecting seed dormancy were detected on chromosomes 3, 5, 7 (two regions) and 8, respectively. Phenotypic variations explained by each QTL ranged from 6.7% to 22.5% and the five putative QTLs explained about 48% of the total phenotypic variation in the BC₁F₅ lines. Except for those of the QTLs on chromosome 8, the Nipponbare alleles increased the germination rate. Five putative QTLs controlling heading date were detected on chromosomes 2, 3, 4, 6 and 7, respectively. The phenotypic variation explained by each QTL for heading date ranged from 5.7% to 23.4% and the five putative QTLs explained about 52% of the total phenotypic variation. The Nipponbare alleles increased the number of days to heading, except for those of two QTLs on chromosomes 2 and 3. The map location of a putative QTL for heading date coincided with that of a major QTL for seed dormancy on chromosome 3, although two major heading-date QTLs did not coincide with any seed dormancy QTLs detected in this study. Received: 10 October 1997 / Accepted: 12 January 1998     

Identification of QTLs associated with tissue culture response through sequencing-based genotyping of RILs derived from 93-11 × Nipponbare in rice (Oryza sativa)

Key message

The performance of callus induction and callus differentiation was evaluated by 9 indices for 140 RILs; 2 major QTLs associated with plant regeneration were identified.

Abstract

In order to investigate the genetic mechanisms of tissue culture response, 140 recombinant inbred lines (RILs) derived from 93-11 (Oryza sativa ssp. indica) × Nipponbare (Oryza sativa ssp. japonica) and a high quality genetic map based on the SNPs generated from deep sequencing of the RIL genomes, were used to identify the quantitative trait loci (QTLs) associated with in vitro tissue culture response (TCR) from mature seed in rice. The performance of callus induction was evaluated by indices of induced-callus color (ICC), induced-callus size (ICS), induced-callus friability (ICF) and callus induction rate (CIR), respectively, and the performance of callus differentiation was evaluated by indices of callus proliferation ability (CPA), callus browning tendency (CBT), callus greening ability (CGA), the average number of regenerated shoots per callus (NRS) and regeneration rate (%, RR), respectively. A total of 25 QTLs, 2 each for ICC, ICS, ICF, CIR and CBA, 3 for CPA, 4 each for CGA, NRS and RR, respectively, were detected and located on 8 rice chromosomes. Significant correlations were observed among the traits of CGA, NRS and RR, and QTLs identified for these three indices were co-located on chromosomes 3 and 7, and the additive effects came from both Nipponbare and 93-11, respectively. The results obtained from this study provide guidance for further fine mapping and gene cloning of the major QTL of TCR and the knowledge of the genes underlying the traits investigated would be very helpful for revealing the molecular bases of tissue culture response.     

粳稻穗部结构性状的QTL分析

利用温带粳稻‘沈农265’和‘丽江新团黑谷’构建的重组自交系群体,在沈阳和哈尔滨两地对15个穗部结构性状进行了QTL分析。共检测到61个相关QTL,其中沈阳检测到的38个QTL在第1、4、6、11和12号染色体上形成了sir-QTL簇;而在哈尔滨检测到的31个QTL也在第3、9和10号染色体上形成了QTL簇。仅有8个QTL是在两地同时被检测到的,分别是控制一次枝梗数#＇．jqPBN4、控制穗长的qPL6和qPL9、控制一次枝梗实粒数的qGNPB4、控制一次枝梗颖花数的qTSNPBJ、控制结实率的qPSSIO、以及控制着粒密度qSD3和qSD9。其中,qPBN4（最高表型贡献率43．2％）、qPL9（最高表型贡献率63．2％）、qGNPB4（最高表型贡献率30．9％）和qSD9（最高表型贡献率42．9％）是主效QTL。通过进一步的分析发现控制穗长qPL9和控制着粒密度qSD94于DEPl所在区间。同时控制一次枝梗数和一次枝梗实粒数的位于第4号染色体长臂端的穗部结构主效QTL,qPBN4qGNPB4极富研究与应用价值。     

Identification of quantitative trait loci controlling rice mature seed culturability using chromosomal segment substitution lines

The genetic transformation efficiency of a rice variety is largely determined by its tissue culturability. Establishment of a highly efficient tissue-culture system has greatly accelerated the wide spread application of transgenic japonica varieties. However, such process for indica rice was hampered because this type of variety is recalcitrant to in vitro culture. This study aimed to map the quantitative trait loci (QTLs) for mature seed culturability using a chromosomal segment substitution lines (CSSL) population derived from a cross between an indica variety “Zhenshan 97B” and a japonica variety “Nipponbare”. The CSSLs consist of 139 lines each containing a single or a few introgression segments, and together covering the whole “Nipponbare” genome. Every CSSL was tested by culturing on the two medium systems developed for the respective indica and japonica parental varieties. The performance of culturability was evaluated by four indices: frequency of callus induction (CIF), callus subculture capability (CSC), frequency of plant regeneration (PRF) and the mean plantlet number per regenerated callus (MNR). All four traits displayed continuous variation among the CSSLs. With the culture system for japonica rice, three CIF QTLs, three CSC QTLs, three PRF QTLs and three MNR QTLs were detected. With the culture system for indica variety, six CIF QTLs, two CSC QTLs, three PRF QTLs and six MNR QTLs were identified, and these QTLs distributed on nine rice chromosomes. Two QTLs of CIF and two QTLs of MNR were detected in both the japonica and indica rice culture system. The correlation coefficients of all the four traits varied depending on the culture systems. These results provide the possibilities of enhancing the culturability of indica rice by marker-assisted breeding with those desirable alleles from the japonica. Lina Zhao and Hongju Zhou have contributed equally to this work.     

The Effect of Rye Chromosomes on Callus Induction and Regeneration in Callus Cultures of Immature Embryos of Wheat–Rye Substitution Lines,Triticum aestivum L. Cultivar Saratovskaya 29–Secale cereale L. Cultivar Onokhoiskaya

The effect of individual rye chromosomes on the induction of callus and the character of its regenerating capacity was studied with cultured immature embryos of wheat–rye (Triticum aestivum L. cv. Saratovskaya 29–Secale cereale L. cv. Onokhoiskaya) substitution lines. The genotypic diversity of the substitution lines proved to significantly affect variation of parameters characterizing the major types of callus cultures, that is, frequencies of embryogenic calli, which are capable of shoot regeneration, and of morphogenic calli, which produce root structures. Functioning in the genotypic background of common wheat cultivar Saratovskaya 29, chromosomes 2R and 3R of rye cultivar Onokhoiskaya stimulated significantly the induction of embryogenic callus highly capable of shoot regeneration. Rye chromosome 2R present in place of chromosome 2D in the common wheat genome suppressed the induction of callus producing root structures. Rye chromosomes 1R and 6R suppressed the induction of embryogenic callus capable of shoot regeneration.     

Genetic analysis of leaffolder resistance in rice

A double haploid(DH)population,which consists of 120 lines derived from anther culture of a typical indica and japonica hybrid 'CJ06'/'TN1',was used to investigate the genetic basis for rice leaffolder resistance.Using a constructed molecular linkage map,five QTLs for rolled leaves were detected on chromosomes 1,2,3,4,and 8.The positive alleles from CJ06 on chromosomes 3,4,and 8 in-creased the resistance to rice leaffolder,and the alleles from TN1 on chromosomes 1 and 2 also enhanced resistance to leaffolde...     

Identification of a novel elite genotype for in vitro culture and genetic transformation of cotton

Hypocotyls of cotton (Gossypium hirsutum L.) cultivars cv. YZ-1, Coker 312 and Coker 201 were inoculated on Murashige and Skoog callus induction medium. YZ-1 exhibited a very high regeneration potential, with 81.9 % of the explants inoculated differentiated into embryogenic callus within 8–10 weeks. During the process of callus maintenance (subculture for 1 to 3 years), the total embryos number in Coker 312 and Coker 201 calli dropped sharply, and the percentage of embryo germination decreased. On the contrary, the callus of YZ-1 consistently maintains a high frequency of plant regeneration after long-time subculture. Transgenic kanamycin-resistant calli of Coker 201 partially lost the ability of somatic embryogenesis and plant regeneration. The stress produced by the transformation procedure slightly affected somatic embryogenesis and plant regeneration of YZ-1, which showed minimum loss of plant regeneration ability.     

Analysis of quantitative trait loci which contribute to anther culturability in rice (Oryza sativa L.)

Anther culturability of rice is significantly different between indica and japonica varieties. A doubled haploid (DH) population was established via anther culture of an indica/japonica hybrid on SK₃ medium, which had been shown particularly suitable for anther culture of indica/japonica hybrids. For analyzing the quantitative trait loci (QTLs) responsible for anther culturability, anthers of the DH lines were again cultured with SK₃ medium and parameters for four traits representing the anther culturability were surveyed and analyzed with the molecular map constructed from the same DH population. The parameters for four major traits were as follows: callus induction frequency (CI), green plantlet differentiation frequency (GPD), albino plantlet differentiation frequency (APD), and green plantlet yield frequency (GPY). All four traits displayed continuous distributions among the DH lines. The correlation coefficients between these traits were also tested and showed that there was no relationship between callus induction and green plantlet differentiation frequencies, but both showed strong positive correlation with the frequency of green plantlet yield. For callus induction frequency, five QTLs were identified on chromosomes 6, 7, 8, 10 and 12. Two QTLs for green plantlet differentiation frequency were located on chromosomes 1 and 9. There was a major QTL for albino plantlet differentiation frequency on chromosome 9. No independent QTL was found for green plantlet yield frequency. The results may be useful in the selection of parents with high response to anther culture for rice haploid breeding and in the establishment of permanent DH populations for molecular mapping.