Abbreviations: LOD, logarithm of the odds ratio; LT-RIL, Lemont ´ TeQing recombinant inbred line; Mbp, mega base pair; MIM, multiple-interval mapping; N1T, node of first tiller on the main culm; QTL, quantitative trait locus; RFLP, restriction fragment length polymorphism; RIL, recombinant inbred line; SLN, seedling leaf number; SSR, simple-sequence repeat; TIL, TeQing-into-Lemont backcross introgression line; TN, tiller number.

Oryza rufipogon (IRGC105491) is a wild relative of cultivated rice, it contains two favorable yield-enhancing genes (yld1.1 and yld2.1) on chromosomes 1 and 2, respectively, which are capable of improving the yield of hybrid rice by 18 and 17%, respectively. SSR markers RM9, RM24, RM5 and RM306 are flanking yld1.1, while RM166 and RM208 are mapped in the close region to yld2.1. These molecular markers tightly linked to the two yield-enhancing genes were used to screen the plants of backcross population between '9311' (one of the top-performing parental lines in super hybrid rice seed production in China) and O. rufipogon. The results were as follows: (1) in BC 2 F 1 population, the percentage of the individuals which contain both of the O. rufipogon alleles at marker loci RM166 and RM9 was 16.8%; (2) 1.5% individuals of total BC 3 F 1 population have all the six linked markers (RM166, RM9, RM5, RM208, RM24, RM306); (3) in BC 4 F 1 population, the percentage of the individuals which contain both of the two O. rufipogon alleles at marker loci RM166 and RM9 was 18.0%. Based on marker genotypes, the individuals, that contain multiple O. rufipogon markers, were selected and used for further backcross and self cross. Many '9311'-type lines with yield-enhancing genes and high yield potential were obtained. After three times self-crossing a stable improved '9311' line was obtained. The results indicated that these molecular markers are feasible for marker-assisted selection (MAS) to screen rice individuals with high yield potential.

Three rice (Oryza sativa L.) germplasm lines designated TIL:383.13 (Reg. No. GP‐144, GSOR 100605), TIL:625 (Reg. No. GP‐145, GSOR 100698), and TIL:634 (Reg. No. GP‐146, GSOR 100702), contain a total of seven alleles of indica rice origin associated with earlier development and increased numbers of tillers during early plant development stages in an elite US tropical japonica rice genetic background having long grain shape and intermediate amylose content and gelatinization temperature. The three high‐tillering introgression lines also exhibit increased panicle number and grain yield and were jointly released in 2016 by the USDA‐ARS and Texas A&M Agrilife Research. The novel alleles for enhanced tiller production originated from ‘TeQing’, an indica rice cultivar from China, and were transferred through a series of backcrossing into lines having a predominantly ‘Lemont’ genetic background. TeQing is well known in the United States for both its high yield and its disease resistance but is not suitable for commercial production due to lodging and poor grain quality. A combination of molecular and phenotypic data was used to identify these three improved germplasm lines from among 123 TeQing‐into‐Lemont backcross introgression lines. A combination of phenotypic and molecular data was used to select three lines from among 123 TeQing‐into‐Lemont backcross introgression lines.

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