QTL Analysis of Shading Sensitive Related Traits in Maize under Two Shading Treatments

During maize development and reproduction, shading stress is an important abiotic factor influencing grain yield. To elucidate the genetic basis of shading stress in maize, an F2:3 population derived from two inbred lines, Zhong72 and 502, was used to evaluate the performance of six traits under shading treatment and full-light treatment at two locations. The results showed that shading treatment significantly decreased plant height and ear height, reduced stem diameter, delayed day-to-tassel (DTT) and day-to-silk (DTS), and increased anthesis-silking interval (ASI). Forty-three different QTLs were identified for the six measured traits under shading and full light treatment at two locations, including seven QTL for plant height, nine QTL for ear height, six QTL for stem diameter, seven QTL for day-to-tassel, six QTL for day-to-silk, and eight QTL for ASI. Interestingly, three QTLs, qPH4, qEH4a, and qDTT1b were detected under full sunlight and shading treatment at two locations simultaneously, these QTL could be used for selecting elite hybrids with high tolerance to shading and high plant density. And the two QTL, qPH10 and qDTS1a, were only detected under shading treatment at two locations, should be quit for selecting insensitive inbred line in maize breeding procedure by using MAS method

Chromosomal location of quantitative trait loci (QTL) for shading sensitive related traits in maize under two shading treatments.

<p>The genetic distance in cM is listed on the left side of each chromosome.</p

The four main climate factors in maize planting season and shading treatment season in 2008 at Xunxian (a) and Zhengzhou (b).

<p>The four main climate factors in maize planting season and shading treatment season in 2008 at Xunxian (a) and Zhengzhou (b).</p

Histogram of the six measured traits in the F2:3 populations at Xunxian (a) and Zhengzhou (b) location.

<p>Histogram of the six measured traits in the F2:3 populations at Xunxian (a) and Zhengzhou (b) location.</p

The comparing value of the six measured traits for shading and full light treatment in the two parents, F₁ and F_2:3 populations at two locations.

<p>The comparing value of the six measured traits for shading and full light treatment in the two parents, F₁ and F_2:3 populations at two locations.</p

The performance of the six measured traits for shade tolerance in the F_2:3 families under two treatments at two locations.

<p>Note:^aPH, plant height; EH, ear height; SD, stem diameter; DTT, day-to-tassel; DTS, day-to-silk; ASI, anthesis-silking interval.</p>b<p>The broad-sense heritability of stover yield and its nutrient components.</p>c<p>The confidence intervals of broad-sense heritability between 5% and 95% significant levels.</p

QTL detected for six measured traits related to shading under two treatments at two locations.

<p>Note: ^aAdditive effect; positive values of the additive effect indicate that the Zhong72 alleles are in the direction of increasing the traits. Dominance effect; positive values of the dominance effect indicate that the heterozygotes have higher phenotypic values than the respective means of the two homozygotes, and negative values indicate that heterozygotes have lower values than the means of the two homozygotes.</p>b<p>A, additive (d/a = 0.00–0.20); PD, partial dominance (d/a = 0.21–0.80); D, dominance (d/a = 0.81–1.20); OD, overdominance (d/a>1.20).</p>c<p>R² contribution rate.</p

Variance analysis of the six measured traits for shading and full light treatment in the F_2:3 populations at two locations.

<p>Note: L, location; B, block; G, genotype; S, shading treatment.</p>*<p>,**: the significant at the 0.05 and 0.01 levels.</p

Fish species abundance and distribution in Wuyishan National Nature Reserve, Jiangxi Province, China. eco.mont (Journal on Protected Mountain Areas Research)|eco.mont Vol. 10 No. 2|

Wuyishan National Nature Reserve is located in the northwest of the Wuyi Mountain Range in northeastern Jiangxi Province. The fish fauna of mountain streams in the nature reserve was investigated seasonally from June 2015 to May 2016. A total of 2 505 samples were collected and classified into 7 families and 16 species. None of those collected in the nature reserve were alien species. Overall, 9 species (56.3% of the total number of fish species collected) were found to be endemic to China. The dominant species were Pseudogastromyzon fasciatus (IRI, 48.23%) and Onychostoma barbatulum (IRI, 46.39%); the common species were Acrossocheilus parallens (IRI, 9.76%), Formosania stigmata (IRI, 4.32%) and Zacco platypus (IRI, 1.15%). There were negative correlations between altitude and total number of species (S), altitude and Margalef index (D), and altitude and Shannon-Wiener index (H). Current threats to the conservation of fish species in the nature reserve were reviewed and management solutions were suggested