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02 August 2022 | Story Leonie Bolleurs | Photo Leonie Bolleurs
Alistair Naidoo, second-year master’s student in Conservation Genetics and full-time technician in the Department of Genetics; Prof Paul Grobler, Head of the Department of Genetics; Prof Gordon Luikart; and Hannah Janse van Vuuren, third-year master’s student in Conservation Genetics.

It is an important and exciting time to be doing research in conservation genetics. This is according to Prof Gordon Luikart, Professor of Conservation Ecology and Genetics at the Flathead Lake Bio Station at the University of Montana in the United States. 

Prof Luikart, whose primary research focus is the application of genetics to the conservation of natural and managed populations, recently delivered a lecture, The Expanding Role of Genetics/omics in Wildlife Research and Conservation, on the Bloemfontein Campus of the University of the Free State (UFS). The lecture, hosted by the Department of Genetics, was attended by a group of students and lecturers in conservation and a number of related fields. 

He is one of the leading scientists in the field of conservation genetics, including integration of genomics in conservation projects. He is also co-author of the textbook Conservation and the Genomics of populations – the current prescribed textbook for GENE3744.

Species threatened with extinction

In 2008, the International Union for Conservation of Nature (IUCN) stated that approximately 10-20% of all vertebrate and plant species are threatened with extinction over the next few decades. In 1984, American biologist Edward O Wilson also said that it will take millions of years to correct the ongoing loss of genetics and species diversity caused by the destruction of natural habitats. “This is the folly our descendants are least likely to forgive us.”

Prof Luikart is of the opinion that genetics has enormous potential to help manage wildlife and prevent extirpation. “My research works to realise this potential and help wildlife managers conserve populations and ecosystems,” he says. 

Conservation managers and biologists have understood the risks of inbreeding for more than 100 years. In his lecture, one of the aspects of genetic conservation he focused on, was the negative effects of inbreeding and how this can be reversed using genetic rescue. 

With the genetic rescue study, they found that the gene flow into recently isolated populations can increase individual fitness and population growth. He proposed that conservation managers should consider genetic principles and rescue as practical and important tools. 

Prof Luikart also provided a list of information that can be retrieved from molecular genetic data to help conservation managers. This includes intel on census and effective population size, gene flow and dispersal, local adaptation and selection, forensics, genetic identification and law enforcement, and disease ecology and transmission. 

Non-invasive genetic monitoring

In terms of detecting gene flow, he focused on a study about non-invasive genetic monitoring that was conducted in the Yellowstone Park. Prof Luikart and a group of students collected the shed hair and faeces of the grizzly bear, obtained from trees and hair traps, which were used as a source of DNA. 

They established, for instance, that inbreeding depression is more common and stronger than previously thought in natural populations. Genetic monitoring, using non-invasive methods as described, has been found to be an effective tool that conservation managers should consider for detecting inbreeding and loss of genome-wide variation.

His research on the bighorn sheep, the alpine ibex, and the black bear informed most of the findings he discussed during his lecture.

News Archive

Sunflowers are satellite dishes for sunshine, or are they?
2016-07-20

Eighty-six percent of South Africa’s
sunflowers are produced in the
Free State and North West provinces.

Helen Mirren, the English actress, said “the sunflower is like a satellite dish for sunshine”. However, researchers at the University of the Free State (UFS) have found that too much of this sunshine could have a negative effect on the growth of sunflowers, which are a major source of oil in South Africa.

According to Dr Gert Ceronio from the Department of Soil, Crop, and Climate Sciences at the UFS, extremely high soil temperatures play a definite role in the sprouting of sunflower seedlings. Together with Lize Henning, professional officer in the department, and Dr André Nel from the Agricultural Research Council, he is doing research on biotic and abiotic factors that could have an impact on sunflowers.

Description: Sonneblom 2 Tags: Sonneblom 2

Various degrees of deformity (bad-left
to none-right) in seedlings of the same
cultivar at very high soil temperatures.
Photo: Dr Gert Ceronio

Impact of high temperatures on sunflower production

The Free State and North West provinces, which produce 86% of South Africa’s sunflowers, are afflicted especially by high summer temperatures that lead to extremely high soil temperatures.

Dr Ceronio says: “Although sunflower seeds are able to germinate at temperatures from as low as 4°C to as high as 41°C, soil temperatures of 35°C and higher could have a negative effect on the vegetative faculty of sunflower seedlings, and could have an adverse effect on the percentage of sunflowers that germinate. From the end of November until mid-January, this is a common phenomenon in the sandy soil of the Free State and North West provinces. Soil temperatures can easily exceed the critical temperature of 43°C, which can lead to poor germination and even the replanting of sunflowers.”

Since temperature have a huge impact not only on the germination of sunflower seeds, but also on the vegetative faculty and sprouting of sunflower seedlings, Dr Ceronio suggests that sunflowers should be planted in soil with soil temperatures of 22 to 30°C. Planting is usually done in October and early November. Unfortunately, this is not always possible, as soil moisture is not optimal for growth. Farmers are then compelled to plant sunflowers later.

Impact of herbicides on sunflower growth

“High soil temperatures, combined with the herbicide sensitivity of some cultivars, could lead to the poor development of seedlings," says Dr Ceronio.

The use of herbicides, such as ALACHLOR, for the control of weeds in sunflowers is common practice in sunflower production. It has already been determined that ALACHLOR could still have a damaging effect on the seedlings of some cultivars during germination and sprouting, even at recommended application dosages.

“The purpose of the continued research is to establish the sensitivity of sunflower cultivars to ALACHLOR when exposed to high soil temperatures,” says Dr Ceronio.

 

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