Influence of Rice Genotypes on Folding and Spinning Behaviour of Leaffolder(Cnaphalocrocis medinalis) and Its Interaction with Leaf Damage

Folding and spinning behavior of Cnaphalocrocis medinalis （Guenee） （Lepidoptera： Pyralidae） in different categories of rice genotypes viz., resistant, susceptible, hybrid, scented, popular and wild rice genotypes were significantly different. Longer leaf selection time and folding time per primary fold; shorter primary fold and whole leaf fold; lower number of binds per primary fold and whole leaf fold were recorded in resistant and wild rice genotypes. In the correlation analysis, it was found that the leaf folding parameters were positively correlated to leaf folder damage whereas the leaf spinning parameters were negatively correlated. Similarly, the morphological characters differed significantly among the chosen genotypes and were related to leaffolder damage. The leaf width and total productive tiller number were positively correlated to leaffolder infestation. Results also indicated that the trichome density and length, leaf length and plant height might contribute to resistance whereas total number of green leaves had no effect on leaffolder infestation. In the scatter plot analysis between leaf folding and spinning characters and leaffolder damage, the genotypes were separated into four groups viz., resistant （TKM6, Ptb 33, LFR831311, Oryza rhizomatis and O. minuta）, moderately resistant （ASD16 and CORH1）, moderately susceptible （ADT36, Pusa Basmati and CB200290） and susceptible （IR36 and TN1）. The present investigation proved that the leaf morphology viz., leaf length and width, plant height and trichome density and length may play a vital role in resistance against rice leaffolder.

Defensive Responses of Rice Genotypes for Resistance Against Rice Leaffolder Cnaphalocrocis medinalis

The experiment was carried out to assess the reaction of different categories of rice genotypes viz., resistant, susceptible, hybrid, scented, popular and wild in response to the infestation by rice leaffolder （RLF）, Cnaphalocrocis medinalis （Guenee） and to explore the possible use of these genotypes in developing RLF-resistant rice varieties. The changes of various biochemical constituents such as leaf soluble protein, phenol, ortho-dihydroxy phenol, tannin and enzymes viz., peroxidase, phenyl alanine ammonia lyase （PAL） were assessed spectrophotometrically in all the rice genotypes before and after RLF infestation. The protein profile was analyzed using sodium dodecyl sulphate-poly acrylamide gel electrophoresis （SDS-PAGE） method. A significant constituent of biochemical content such as tannin, phenol and ortho-dihydroxy phenol has been increased along with enzyme activities of peroxidase and PAL in the infested resistant （Ptb 33, TKM6 and LFR831311） and wild rice genotypes （Oryza minuta and O. rhizomatis）. A decrease in leaf protein content was evident invariably in all the infested rice genotypes. It is also evident that the contents of biochemicals such as phenol, ortho- dihydroxy phenol and tannin were negatively correlated with leaffolder damage. However, leaf protein content was positively correlated with the damage by rice leaffolder. SDS-PAGE analysis for total protein profiling of healthy and C. medinalis-infested genotypes revealed the enhanced expression of a high molecular weight （〉 97 kDa） protein in all the genotypes. Besides, there was also an increased induction of a 38 kDa protein in C. medinalis infested resistant genotypes, which was absent in uninfested plants. The present investigation proved that the elevated levels of biochemicals and enzymes may play a vital role in rice plants resistance to RLF.

通过体外诱导突变及筛选来改良果树作物特性的研究进展(英文)

突变会导致栽培作物一个或多个特殊性状的改变,以突变为基础的植物品质的改良,会使果树业的发展获得极大的促进。传统诱导突变的方法应用于果树作物,常受限于外植体来源,并且耗费大量的时间及场地。体细胞变异结合物理化学诱变法可被视作改良果树作物的一种手段,并且在一些果树作物中获得了成功。这使我们有理由认为体外诱导变异是改良果树作物的品质及其抗逆性的一种很有效的潜在途径。本文讨论了大量的与果树培育有关的突变诱导、变异体筛选、大田评估方法等综合使用的实例及研究进展。