Characteristic analysis of tetra-resistant genetically modified rice

In this study, the characteristic of three transformants named as B1C106-1, B1C106-2, and B1C106-3 were studied that carried three innate resistant genes Bph14, Bph15, and Xa23, and two enthetic resistant genes CrylCa# and Bar. The five resistant genes were all verified by PCR and the two enthetic genes were identified in single copy insertion by Southern blot. At tillering stage, the CrylC and PAT （phosphinothricin acetyl transferase） protein contents in leaf, sheath, and stem of T2 generation were in the similar pattern： leaf〉stem〉sheath, and showed significant difference （P〈0.01） among three organs. The average contents of CrylC protein in plant of B1C106-1, B1C106-2, and BIC106-3 were 12.95, 6.57, and 11.30 μg g-1, respectively, and showed significant difference （P〈0.01） among them. However, the average contents of PAT in plant of B1C106-1, B1C106-2, and B1C106-3 were 28.54, 27.66, and 28.02 pg g-1, respectively, and there were no significant difference among three transformants. The glufosinate tolerable concentration of three transformants of T3 generation reached at least 6 g L-1, and the mortality of rice leaf rollers were above 97.4% in 5 days after being fed with fresh transformants＇ leaves. The CrylC protein toxicity was also assessed by silkworms, and the mortality of silkworms feeding mulberry leaves smeared with Cry1C protein extracts of leaves of B1 C106-1, BIC106-2, and B1 C106-3 were 90, 67.8, and 87.8%, respectively, that were positive correlation （r=0.993） with CrylC protein contents in plant of three transformants. The three transformants also maintained high resistance to brown planthopper and bacterial blight as the original version. The above results indicate the tetra-resistant rice germplasm was well-developed by pyramiding innate and enthetic resistant genes in an elite line to provide with resistances of glufosinate, rice leaf roller, brown planthopper, and bacterial blight.

Breeding of a Natural Green Cocoon Quaternary Hybrid Combination Xiangcailu No.1 for Spring Rearing

The breeding activities aimed to create a natural green cocoon variety for spring rearing with the characteristics of stable natural cocoon color,easy rearing and good silk quality.Four different lines from the excellent silkworm variety Jingsong×Haoyue were taken as recurrent parents,using the natural green cocoon variety G 9202 as donor parent.After other excellent parents were introduced to cross with these different lines,four new breeding materials were selected by recurrent backcross breeding.The characters of these breeding materials showed not only natural green cocoon but also excellent comprehensive traits.A naturally colored cocoon quaternary hybrid with excellent practical characters was selected based on multiple hybrids.It is suitable for spring rearing in Yangtze valley which includes Hunan Province.It was approved by Hunan Provincial Crop Variety Approval Committee and designated Xiangcailu No.1 in 2016.

Verification of Glyphosate Resistance, Lepidopteran Resistance and Wide Compatibility of Male Sterile Line E1C4008S in Rice

Weeds and insect pests are two important biotic stresses resulting in yield loss in rice, and wide compatibility is the essential characteristic of breeding inter-subspecific hybrid rice. This study focused on glyphosate resistance, lepidopteran resistance and wide compatibility as well as identification of molecular and some agronomic characteristics of transgenic male sterile line E1 C4008 S. The results indicated that glyphosate resistance gene Epsps^# and lepidopteran resistance gene Cry1 ca^# were transferred into japonica wide compatibility male sterile line 4008 S by Agrobacterium-mediated method, and four independent transformation events named E1 C4008 S-1, E1 C4008 S-2, E1 C4008 S-3 and E1 C4008 S-4 were obtained, in which E1 C4008 S-3 and E1 C4008 S-4 were of single copy insertion. The EPSPS protein contents of E1 C4008 S-3 and E1 C4008 S-4 in different organs were significantly different both in descending order of leaf > stem > root, and ranged from 300.58 to 1410.69 μg/g at the tillering stage. The glyphosate tolerable concentration(dosage) of E1 C4008 S-3 and E1 C4008 S-4 reached at least 16 g/L(54.42 kg/hm^2), and the seeds of E1 C4008 S-4 can germinate normally on the medium containing 1 g/L glyphosate. The CRY1 C protein contents of E1 C4008 S-3 and E1 C4008 S-4 in different organs were significantly different both in descending order of leaf > stem > root, and ranged from 0.62 to 2.43 μg/g at the tillering stage. The larvae mortalities of rice leaf rollers fed on leaves of E1 C4008 S-3 and E1 C4008 S-4 for 5 d were 95.35% and 97.77%, respectively, while the average mortalities of silkworms fed with protein extracts from leaves of E1 C4008 S-3 and E1 C4008 S-4 reached 94.55% and 83.64%, respectively. The results suggested that wide compatibility and evaluated agronomic traits of E1 C4008 S-4 were not significantly changed by insertion of the exogenous genes. Overall, a novel male sterile germplasm with glyphosate resistance, lepidopteran resistance and wide compatibility was verified to be developed in rice.