Is backcrossing a good strategy for improving elite lines for quantitative traits in general? Results reported here demonstrate the effectiveness of a backcrossing program for improving quantitatively inherited disease resistance traits, which are strongly influenced by the environment. Through backcross breeding, we were able to improve an important commercial inbred line, FR1064, for ear rot and fumonisin contamination resistance without significantly lowering its yield potential, even with the use of a donor line with poor agronomic potential. Following one generation of selection on advanced backcross-derived lines, gains were observed for the primary trait of interest in advanced inbred generations. Following two generations of selection, we improved potential performance for ear rot resistance and reduced fumonisin accumulation in the 19 selected lines without significantly affecting important agronomic characteristics such as plant height, ear height, or flowering time compared to the recurrent parent, FR1064. The 19 selected lines were also significantly more resistant to ear rot under inoculated conditions than the FR1064 topcross without exhibiting significant reductions in topcross grain yield or other agronomic traits. Several individual lines were identified that were not statistically different from GE440 for ear rot or fumonisin content as inbreds or from the GE440 topcross for ear rot. These lines exhibited topcross yields comparable to the FR1064 topcross, although they were not competitive with commercial check yields. Thus, from a practical standpoint, the backcrossing method was effective at improving quantitative disease resistance in an elite commercial line using an unadapted donor parent. We also genotyped selected lines at DNA markers linked to ear rot and fumonisin resistance quantitative trait loci (QTL) identified in the BC1 generation of this cross to determine which QTL demonstrated allele frequency shifts due to selection.

A new spray chrysanthemum cultivar ‘Prima Donna’ was released by National Institute of Horticultural and Herbal Science (NIHHS), Rural Development Administration (RDA), in 2008. The cross was made between ‘Plano’ and ‘Yeonja’ in 2005. Trials were conducted from 2006 to 2008 for the evaluation and selection of this cultivar, including shading cultures in summer and retarding cultures in spring. The natural flowering time of ‘Prima Donna’ is late October, but year-round flowering is possible by photo-periodic control. The cultivar has single type flowers with pink petals, green center and good inflorescence. The growth of plant is very vigorous. The diameter of flower is 7.0cm. The number of flowers per stem and petals per flower are 13 and 42, respectively. Days to flowering under the short day treatment is about 59 and its vase life is 26.1 days in autumn season.

A new poinsettia cultivar 'Scarlet' was bred by the National Horticultural Research Institute (NHRI) in 2006. A cross was made between 'Christmas Eve', a variety with dark green leaves and dark red bracts, and 'Red Velvet', a red colored variety in 2003. 'Scarlet' was finally selected in 2006 after investigating the growth and flower characteristics from 2004 to 2006. 'Scarlet' has bright red colored and elliptic bracts and has absent or very weak intensity of rugosity between veins in bract. In comparison with the check variety, 'Red Velvet', plant height is tall, leafblade is long and narrow. Petiole is also longer than that of 'Red Velvet'. Short day response is fast and its bracts are fully colored 7 weeks after short day commencement.

A new poinsettia cultivar 'Miss Maple' was bred by the National Horticultural Research Institute (NHRI) in 2006. A cross was made between 'Sonora Red', a variety with short plant height, dark green leaves and dark red bracts, and 'Cranberry Punch', a deep pink colored variety in 2003. 'Miss Maple' was finally selected in 2006 after investigating the growth and flower characteristics from 2004 to 2006. 'Miss Maple' has light red colored and obovate bracts, and has weak intensity of rugosity between veins in bract. Fully colored transitional leaves are so deeply lobed that they resemble the leaves of maple. Plant height is shorter than that of 'Cranberry Punch', the check variety. Short day response fast and its bracts are fully colored 7 weeks after short day commencement.