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05 April 2024 | Story DR NITHA RAMNATH
The Vice-Chancellor and Principal of the University of the Free State, Prof Francis Petersen, has the pleasure of inviting you to a guest lecture presented by H.E. Dr Reuben E Brigety, the United States Ambassador to South Africa.

Date: Tuesday 23 April 2024
Time: 15:00-16:00
Venue: Centenary Complex, Bloemfontein Campus

RSVP here by no later than 19 April 2024.

About the speaker

Reuben E Brigety II was confirmed as the 29th United States Ambassador to the Republic of South Africa on 21 July 2022.

Previously, he served as the 17th Vice-Chancellor of the University of the South and Mayor of Sewanee from June 2020 until December 2021, and as the Dean of the Elliott School of International Affairs of the George Washington University from 2015 to 2020. Ambassador Brigety’s most recent diplomatic assignment was serving as the US Representative to the African Union and US Permanent Representative to the UN Economic Commission for Africa from September 2013 to September 2015. Previously, Ambassador Brigety served as the Deputy Assistant Secretary of State in the Bureau of African Affairs and as Deputy Assistant Secretary of State in the Bureau of Population, Refugees, and Migration.

A native of Jacksonville, Florida, Ambassador Brigety also held appointments as Assistant Professor of Government and Politics at George Mason University and at the School of International Service at the American University between August 2003 and April 2009. In addition, Ambassador Brigety was a researcher with the Arms Division of Human Rights Watch (HRW) from August 2001 to May 2003, where he conducted research missions in Afghanistan and Iraq. Before joining HRW, Ambassador Brigety was an active-duty US naval officer and held several staff positions in the Pentagon and in fleet support units.

Ambassador Brigety is a 1995 Distinguished Midshipman Graduate of the US Naval Academy, where he earned a BSc in Political Science (with merit), served as the Brigade Commander, and received the Thomas G Pownall Scholarship. He also holds an MPhil and a PhD in International Relations from the University of Cambridge, England, as well as a Doctor of Humane Letters (honoris causa) from Old Dominion University. Ambassador Brigety is a life member of the Council on Foreign Relations, a recipient of the council’s International Affairs Fellowship, and a fellow of the American Academy of Diplomacy.He is married to Dr Leelie Selassie, and together they have two sons.

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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