scholarly journals Selection Signatures Underlying Dramatic Male Inflorescence Transformation During Modern Hybrid Maize Breeding

Genetics ◽  
2018 ◽  
Vol 210 (3) ◽  
pp. 1125-1138 ◽  
Author(s):  
Joseph L. Gage ◽  
Michael R. White ◽  
Jode W. Edwards ◽  
Shawn Kaeppler ◽  
Natalia de Leon
2018 ◽  
Author(s):  
Joseph L. Gage ◽  
Michael R. White ◽  
Jode W. Edwards ◽  
Shawn Kaeppler ◽  
Natalia de Leon

AbstractInflorescence capacity plays a crucial role in reproductive fitness in plants, and in production of hybrid crops. Maize is a monoecious species bearing separate male and female flowers (tassel and ear, respectively). The switch from open-pollinated populations of maize to hybrid-based breeding schemes in the early 20th century was accompanied by a dramatic reduction in tassel size, and the trend has continued with modern breeding over the recent decades. The goal of this study was to identify selection signatures in genes that may underlie this dramatic transformation. Using a population of 942 diverse inbred maize accessions and a nested association mapping population comprised of three 200-line biparental populations, we measured 15 tassel morphological characteristics by manual and image-based methods. Genome-wide association studies identified 242 single nucleotide polymorphisms significantly associated with measured traits. We compared 41 unselected lines from the Iowa Stiff Stalk Synthetic (BSSS) population to 21 highly selected lines developed by modern commercial breeding programs and show that tassel size and weight were reduced significantly. We assayed genetic differences between the two groups using selection statistics XP-EHH, XP-CLR, and FST. All three selection statistics show evidence of selection at genomic regions associated with tassel morphology relative to genome-wide null distributions. These results support the tremendous effect, both phenotypic and genotypic, that selection has had on maize male inflorescence morphology.


2006 ◽  
Vol 54 (3) ◽  
pp. 343-350 ◽  
Author(s):  
C. F. H. Longin ◽  
H. F. Utz ◽  
A. E. Melchinger ◽  
J.C. Reif

The optimum allocation of breeding resources is crucial for the efficiency of breeding programmes. The objectives were to (i) compare selection gain ΔGk for finite and infinite sample sizes, (ii) compare ΔGk and the probability of identifying superior hybrids (Pk), and (iii) determine the optimum allocation of the number of hybrids and test locations in hybrid maize breeding using doubled haploids. Infinite compared to finite sample sizes led to almost identical optimum allocation of test resources, but to an inflation of ΔGk. This inflation decreased as the budget and the number of finally selected hybrids increased. A reasonable Pk was reached for hybrids belonging to the q = 1% best of the population. The optimum allocations for Pk(q) and ΔGkwere similar, indicating that Pk(q) is promising for optimizing breeding programmes.


2008 ◽  
Vol 117 (2) ◽  
pp. 251-260 ◽  
Author(s):  
Thilo Wegenast ◽  
C. Friedrich H. Longin ◽  
H. Friedrich Utz ◽  
Albrecht E. Melchinger ◽  
Hans Peter Maurer ◽  
...  

2006 ◽  
Vol 28 (1) ◽  
pp. 169-175 ◽  
Author(s):  
Kalinka Carla Padovani de Carvalho Salgado ◽  
das Graças Guimarães Carvalho Vieira ◽  
Édila Vilela de Resende Von Pinho ◽  
Cláudia Teixeira Guimarães ◽  
Renzo Garcia Von Pinho ◽  
...  

One of the main features that confer high quality to the seed is its genetic purity, in which one of the major causes of contamination is the self-pollination of the female parent. Up to date, there is no accurate and fast methods for detecting such contamination. Thus, this work was carried out to certify the genetic purity in seeds of hybrid maize using different biochemical and DNA-based markers. Two single-cross hybrids and their parental lines derived from the maize breeding program at UFLA were evaluated by isoenzymatic pattern of alcohol dehydrogenase (ADH), esterase (EST), acid phosphatase (ACP), glutamate-oxaloacetate transaminase (GOT), malate dehydrogenase (MDH), isocitrate dehydrogenase (IDH), phosphoglucomutase (PGM), 6-phosphoglucomate dehydrogenase (PGDH), catalase (CAT) and ß-glucosidade (ßGLU) and by microsatellites markers. The enzymatic systems that were able to distinguish the hybrids from their parental line were the catalase, the isocitrate dehydrogenase and the esterase. The esterase showed a Mendelian segregation pattern for UFLA 8/3 hybrid, that enables a safer genetic purity certificate. Microsatellites were able to differentiate the hybrid lines and the respective parental lines. Moreover, this technique was fast, precise and without environment effects. For microsatellites, the amplification pattern was identical when young leaves or seeds were used as DNA source. The possibility of using seeds as DNA source would accelerate and facilitate the role process of the genetic purity analysis.


2020 ◽  
Vol 2 (4) ◽  
pp. 15-23
Author(s):  
E. B. Khatefov ◽  
B. R. Shomakhov ◽  
R. S. Kushkhova ◽  
R. A. Kudaev ◽  
Z. T. Khashirova ◽  
...  

Abstract. Hybrid maize breeding requires constant renewal of the source material. In this regard, broadening of genetic variation in parental lines is one of the primary tasks in heterotic hybrid breeding programs. The use of reverse diploid inbred lines derived from a tetraploid population is considered as an innovative approach to achieve this goal.Results. The investigated material comprised 106 reverse diploid (rediploid) inbred lines originating from diploid plants selected in segregating selfed progenies of triploid populations and consequently subjected to inbreeding, while triploid populations resulted from a cross between plants of a tetraploid population with a broad genetic basis and a diploid line. The use of a system of crosses with 37 sterile testers belonging to different FAO maize maturity groups allowed the evaluation of the rediploid lines’ combining ability and the response to M and C types of CMS. Field tests were conducted in 2019 in the steppe zone of Kabardino-Balkaria. Forty-six lines (43.3%) with the combining ability ranging from ultra-high to good, and 78 lines (73.6%) maintaining the CMS character were identified. Among them, 59 lines (55.7%) were maintainers for the M type CMS, 15 lines (14.1%)  for C type CMS, and 4 lines maintained sterility for both CMS types. Sixteen lines (15.1%) restored pollen fertility of the forms with M type CMS, 11 lines (10.4%) were restorers for the C-type and one line turned out to be a universal restorer for both CMS types. Ranking by the “sprout - flowering of ears” interstage period duration showed that most of the lines (66.0%) with the ability to maintain sterility or restore male fertility of M and C CMS types, as well as with the combining ability from ultrahigh to good (32.6%) fell into the group with the flowering period duration of 51-55 days. According to the results of the harvested grain moisture assessment, the hybrids ♀(РГС246с × OL213) × ♂92с5986·2·3, ♀714М  ×  ♂1/67-1 and ♀714М  ×  ♂92н136-4, with the values of 13, 6%, 13.9%, 14.0%, respectively, were identified. The hybrids ♀714М × ♂1/67- 1 and ♀(OL563С × KL1392) × ♂92с0653 2 1 2 were characterized by the maximum value of the selection index, i.e. 5.03 and 5.13, respectively.Conclusions. The results of the studies showed the breeding value of rediploid lines as an initial material for hybrid maize breeding. 


2006 ◽  
Vol 112 (5) ◽  
pp. 903-912 ◽  
Author(s):  
C. Friedrich H. Longin ◽  
H. Friedrich Utz ◽  
Jochen C. Reif ◽  
Wolfgang Schipprack ◽  
Albrecht E. Melchinger

2018 ◽  
Vol 110 (4) ◽  
pp. 1209-1216 ◽  
Author(s):  
XingMing Fan ◽  
Yaqi Bi ◽  
Yudong Zhang ◽  
Daniel Jeffers ◽  
XingFu Yin ◽  
...  

2005 ◽  
Vol 52 (4) ◽  
pp. 421-438 ◽  
Author(s):  
G. Hadi

Several generations of maize breeders contributed to the establishment of genetic resources in Eastern Central Europe by developing open-pollinated varieties, inbred maize hybrids and parental lines successfully grown on large areas and differing from those found in the North American Corn Belt and in other regions of Europe. In some cases they used unusual methods or used known methods in an unorthodox fashion. The Caribbean Flints brought to Hungary from Spain by the Turks in the 16th century played an important role in the development of the Eastern Central Europe genetic resources and dominated Hungarian maize production for nearly four hundred years. In the early 19th century these genetic stocks of Caribbean origin were supplemented by Andean popcorn (Chutucuno Chico, Chutucuno Grande), introduced into Hungary from Italy for human consumption and export purposes and to a lesser extent by Northern Flints (Pennsylvania 8-row). Under the influence of American maize exhibitions in the 19th century, Southern Dents (especially Gourdseed, but also Shoepeg, Hickory King and Tuxpan) and Corn Belt Dents (Queen of the Prairie, Iowa Goldmine, Leaming, and to a lesser extent Funk Yellow Dent) gained ground. In Eastern Central Europe dent varieties were late maturing, so they were crossed, primarily with early-maturing hard flints, and also with early variants of the Caribbean type Old Hungarian Yellow Flint, in order to produce new varieties, which then dominated maize production in the first half of the 20th century. In the early years of hybrid maize breeding, the breeders relied greatly on local, productive, adapted sources. As the result of hybrid maize breeding in Eastern Central Europe, two distinct gene pools developed, which it is thought could contribute to a further increase in maize yield averages through an improvement in genetic variability. These two gene pools are the Ruma and Mindszentpuszta (MYD) heterosis sources. At least 30 lines of Ruma origin and 19 of MYD origin have been successfully used in the development of commercial hybrids. From the point of view of breeding early flint × dent hybrids, the European early multi-rowed hard flints, which developed locally, independently of the American Northern Flints, could also be of interest. Less significant varieties and lines that were grown successfully at one time or another could be used as genetic reserves for the development of new variations. The paper will discuss the varieties popular between 1880 and 1983, providing more detailed data on 13 open-pollinated varieties, 2 variety hybrids, 41 inbred hybrids and 40 successful lines.


Sign in / Sign up

Export Citation Format

Share Document