Screening Test of Small Seedless Watermelon Varieties in Beijing Area

[Objectives]This study was conducted to select small seedless watermelon varieties with excellent quality and high yield suitable for planting in Beijing.[Methods]Under the conditions of facility cultivation in Beijing,a screening test was conducted on seven small seedless watermelon varieties for growth process,field traits,yield traits,fruit quality,and disease resistance.[Results]Varieties Mitong,Motong and Tianbao Xiaowuzi had a short growth period and relatively stable growth,and bore fruit easily,and their female flowers were closely spaced.Their yields exceeded 60000 kg/hm~2,ranking in the top three among all varieties.The fruit had a thin skin,a bright red flesh color,and a high mass fraction of soluble solids in the center.The flesh was tight or crispy,and tasted good.They also showed good disease resistance.Overall,they showed excellent comprehensive agronomic traits,and are thus suitable for facility cultivation in Beijing and its surrounding areas.[Conclusions]This study provides a theoretical basis for the upgrading of varieties and the increase in production and farmers'income in the suburbs of Beijing.

Screening and Application of Oilseed Rape Varieties with High Yield and High Harvest Index

28 oilseed rape Pol CMS three-line hybrid combinations diallel-crossed were compared in the yield and harvest index and analyzed on the correlation between the experimental yields and harvest indexes in this study. The correlation coeffcient was only 0.365 4, lower than a signifcant level, which indicated that there was no signifcant positive （or negative） correlation between the economic yields and the harvest indexes in oilseed rape. Among them, 8 hybrid combinations including 7 with a harvest index〉0.30 and one with a harvest index〈0.27 increased signifcantly in the yields compared with the control, and then were screened for production experiment. Under different cultivation methods, all the 8 combinations had a stable harvest index, and the combinations with higher harvest indexes also had a stable performance in yields. An oilseed rape variety Fengyou 737 with higher yield and harvest index selected through a further screening was grown with the harvest indexhigher than 0.33 whether transplanted or directly seeded in Yangtze River Basin Demonstration Area, demonstrating stable high yields as well as good ecological adaptability. The combination of yield and harvest index in the study is conducive to breeding a new oilseed rape variety with stable yields and good tolerance to close planting.

Early Screening of Rice Varieties with High Essential Amino Acids by Aseptic Seedling Method

With 5 rice varieties( Yifeng 3321,Yifeng 3315,Yifeng 3317,Yifeng 45,Yifeng 14-24) as the experimental objects,the aseptic seedling method was used to culture the rice seeds,and the HPLC was used to determine the content of amino acids in aseptic rice seedlings as well as the total content of 8 kinds of essential amino acids and the content of protein. And the content of protein and amino acids in the polished rice of 5 varieties was detected,and the analysis of variance was performed for screening of the varieties containing high essential amino acids. The rice with high essential amino acids could be produced to meet people's rice quality requirements. The analysis of variance indicated that there were significant differences( F = 39. 262,p = 0. 01) in the content of essential amino acids among 5 kinds of rice varieties. By the Duncan's multiple comparison,the differences among rice varieties were calculated to obtain screening results. The aseptic seedlings:Yifeng 3321(7. 268),Yifeng 3315(6. 395),Yifeng 3317(5. 698),Yifeng 45(5. 567),Yifeng 14-24(5. 190). Rice: Yifeng 3321(2.998),Yifeng 14-24(2. 627),Yifeng 3317(2. 611),Yifeng 3315(2. 503),Yifeng 45(2. 281). Based on the estimated human daily requirement of essential amino acids and amino acids requirement pattern,it was found that the polished rice of 5 varieties was up to standard.The variety with the highest content of essential amino acids was Yifeng 3317(3830 mg/100g),followed by Yifeng 3321(3770 mg/100 g).The results showed that the high quality rice variety in this experiment was Yifeng 3321.

Evaluation and screening for resistance of some varieties(lines)to major diseases and insect pests of rice

During 1984-1988,2,231 varieties(lines)from International Rice Testing Program(IRTP)were evaluated and screened for resistance to riceblast(Bl),bacterial blight(BB),sheath blight