Breeding of a New Thick Red Apple Cultivar Jihong

Jihong is a variation bred by Shijiazhuang Pomology Institute of Hebei Academy of Agriculture and Forestry Sciences. The fruit is big,average fruit weight is234 g,the largest is 500 g. The fruit skin is thick red, easy coloring and the coloring index is 95%. The flesh is crisp, juicy,and moderate sweet-sour taste. The soluble solid content is 16.0%,and it has good qualities,high and stable yield. It is mature at the end of October.

Genetic diversity and elite gene introgression reveal the japonica rice breeding in northern China

Abundant genetic diversity and rational population structure of germplasm benefit crop breeding greatly.To investigate genetic variation among geographically diverse set of japonica germplasm,we analyzed 233 japonica rice cultivars collected from Liaoning,Jilin and Heilongjiang provinces of China,which were released from 1970 to 2011 by using 62 simple sequence repeat（SSR） markers and 8 functional gene tags related to yield.A total of 195 alleles（N_a） were detected with an average of 3.61 per locus,indicating a low level of genetic diversity level among all individuals.The genetic diversity of the cultivars from Jilin Province was the highest among the three geographic distribution zones.Moreover,the genetic diversity was increased slightly with the released period of cultivars from 1970 to 2011.The analysis of molecular variance（AMOVA） revealed that genetic differentiation was more diverse within the populations than that among the populations.The neighbor-joining（NJ） tree indicated that cultivar clusters based on geographic distribution represented three independent groups,among which the cluster of cultivars from Heilongjiang is distinctly different to the cluster of cultivars from Liaoning.For the examined functional genes,two or three allelic variations for each were detected,except for IPA1 and GW2,and most of elite genes had been introgressed in modem japonica rice varieties.These results provide a valuable evaluation for genetic backgrounds of current japonica rice and will be used directly for japonica rice breeding in future.

High-efficiency breeding of early-maturing rice cultivars via CRISPR/Cas9-mediated genome editing

Rice is a staple food for more than half of the human population.It has been estimated that by 2030,40%more rice needs to be produced in order to meet the growing demand（Khush,2005）.One of the strategies to improve rice productivity is to enlarge rice growth areas, such as the northward expansion of the growth region in Heilongjiang Province, the northernmost region of China （Li et al., 2015）. However, the northward cultivation is accompanied with daylength extension and temperature decrease, which are unfavor- able for rice, a tropical short-day plant, to complete flowering and seed setting. Thus, the need for early-maturing rice cultivars with extremely low photoperiod sensitivity is urgent.

Root morphology in response to nitrogen supply in mid-season indica rice cultivars released in different decades

Dear Editor,Roots,as a major organ of plants,are involved in nutrient and water acquisition,and might play a vital role in yield increase and efficient N absorption with genetic improvement.Because of the great differences in growth period and pattern between the old and new rice cultivars,it is difficult to clarify how genetic improvements contribute to root growth in rice.