Thesis (M.Sc. (Agricultural Agronomy)) --University of Limpopo, 2015 / Refer to document / Department of Agriculture Forestry and Fisheries (DAFF)

Lietuvos žemdirbystės instituto Javų selekcijos skyriaus devynlaukėje sėjomainoje 2008 - 2009 metais buvo atlikti žieminių kviečių ( Triticum aestivum. L) konkursiniai bandymai, kuriuose buvo tirta 18 perspektyvių selekcinių linijų ir palyginta su standartine veisle Zentos. Atlikus šiuos bandymus nustatyta, kad didžiausią derlių išaugino Flair/Ansgar (8,03 t ha-1) ir Flair/Lut 9-329 DH (7,84 t ha-1) selekcinių linijų kviečiai atitinkamai 17,2 ir 14,4 proc., lyginant su kontroline Zentos (6,85 t ha-1) veisle. Žieminių kviečių, skirtų krakmolo gamybai, atrinktos mažiausiai baltymingos, kurių grūduose baltymų kiekis buvo atitinkamai 8,5 proc. ir 8,7 proc., lyginant su Zentos (10.8 proc.) veisle. Daugiausiai krakmolo, lyginant su kontroline Zentos (70,2 proc.) veisle, sukaupė Olivin/Cubus DH (73,3 %), Biscay/Dream (73 %.), Dream/Bill (72,6 %) selekcinės linijos. Selekcinės linijos Tarso / Lut 96-3 (68,8 proc.) ir Dream / 91002 G 2.1 (70,1 proc.) brokuotinos dėl mažo krakmolo kiekio grūduose. Optimalus produktyvių stiebų skaičius 170,3; 179,0 ir 200 vnt m-2 išauginęs krakmolingiausius grūdus yra atitinkamai Dream/Bill, Olivin/Cubus DH ir Biscay/Dream selekcinių linijų. / In 2008-2009 a 9-field crop rotation of the Grain Crop Selection Department of the Lithuanian Institute of Agriculture was used for the purpose of carrying out experimentations with winter wheat (Triticum aestivum. L) that involved a research of 18 prospective breeding lines and their comparisons with the standard breed Zentos. Experimentations showed that maximum yield was obtained from Flair/Ansgar (8,03 t ha-1) and Flair/Lut 9-329 DH (784 t ha-1) breeding lines amounting for 17,2 percent and 14,4 percent respectively, when compared to the control breed Zentos (6,85 t ha-1). Breeding lines (Flair/Ansgar, Olivin/Cubus DH) with the least protein content were selected from the winter wheat breeds particularly intended for the purpose of starch production; their protein content was 8,5 percent and 8,7 percent, respectively when compared to Zentos breed (10,8 percent). The highest starch content was found in wheat of breeding lines Olivin/Cubus DH (73,3 percent), Biscay/Dream (73 percent), Dream/Bill (72,6 percent) when compared to the control breed Zentos (70,2 perent). Breeding lines Tarso / Lut 96-3 (68,8 percent) and Dream / 91002 G 2.1 (70,1 percent) were considered to be worth discarding due to the low starch content in grain. The optimum number of productive stems was obtained from breeding lines Dream/Bill, Olivin/Cubus DH and Biscay/Dream and amounted for 170,3, 179,0 and 200 stem units per m-2, respectively.

Thesis (M.Sc. (Agriculture Agronomy)) -- University of Limpopo, 2020 / Pigeonpea (cajanus cajan [L] Millsp.) is a legume crop which is grown mainly in the Semi-Arid Tropical (SAT) regions and it is mostly cultivated for its edible seeds. It has been identified as a possible substitute crop which can be bought by all people and it can also provide an acceptable amount of nutrition and protein in particular as it is not an expensive source of protein when compared to animal protein. Its ability to tolerate drought and fix atmospheric nitrogen makes it suitable for marginal areas with low rainfall and poor fertility. However, it remains one of the underutilized crops due to limited research on the crop’s diversification and adaptation. Smallholder farmers in the Limpopo Province cultivate landraces pigeonpea varieties that are characterized by late maturity, low grain yield and are sensitive to photoperiod and this makes it difficult for the cultivars to flower early and produce reasonable yield. The objectives of the study were to evaluate the nitrogen fixation, yield and yield components of exotic elite pigeonpea genotypes. The experiment was conducted at the University of Limpopo Experimental farm (Syferkuil) in Mankweng during the 2017/18 growing seasons. The trial was carried out in a Randomized Complete Block Design (RCBD) consisting of three replications. A total of 18 elite pigeonpea breeding lines obtained from ICRISAT in Kenya were planted at an inter-row and intra-row spacing of 1m and 0.5m respectively, in a row of 5m length with an alley way of 2m between the blocks. The standard management practices for pigeonpea were used for weed and insect control. The agronomic data collected included the number of days to first and 50% flowering, the number of days to 90% maturity, canopy width (m), plant height (m), peduncle length (m), number of primary branches, number of pods per plant, pod length (cm), hundred seed weight (g), calcium content, sodium content, magnesium content, phosphorus content, potassium content, iron content, zinc content, proportion of legume N derived from the fixation of atmospheric N2 (%Ndfa), amount of nitrogen fixed and the grain yield (kg.ha-1 ). The generated data was subjected to an analysis of variance using the Statistix 10.0 software. The Least Significance Difference (LSD) was used to separate the means that showed significant differences at an alpha level of 0.05. The results revealed significant differences in nearly all the pigeonpea variables (pod length, number of seed per pod, nutrient elements and the number of primary branches). Across genotypes, the number of days to 50% flowering ranged from 95 to 130 days, while the number of days to 90% maturity ranged from 172 to 220 days, with variety ICEAP 01154-2 being the earliest to flower and mature. Tall plants were observed by variety ICEAP 01541 (2.01m) followed by ICEAP 00902 (1.99m) and ICEAP 00850 (1.90m). Breeding line ICEAP 00673-1 recorded long peduncles with a mean of 0.94m. The number of pods per plant had a range between 56 and 482, while the pod length varied from 2.03 to 8.82cm. Variety ICEAP 00673-1 exhibited the highest number of pods per plant and with longest pods. The 100 seed weight varied from 9.43 to 16.97g among the genotypes. The higher calcium amount was observed in verities ICEAP 00979-1 with an average of 556 mg/L and the highest iron content was observed in ICEAP 01172-2 (14 mg/L). The potassium content ranged between 24 mg/L to 110 mg/L, with the variety ICEAP 00540 having the highest and the variety ICEAP 00850 having the lowest content. The sodium content ranged from 15 to 85.1 mg/L, with the variety ICEAP 01154-2 being the highest and the variety ICEAP 01147-1 having the lowest sodium content. The highest magnesium content was observed in ICEAP 00673-1 (141 mg/L). The phosphorus content ranged from 24.5 to 3.77 mg/L and the highest zinc content was observed in ICEAP 01541 and in ICEAP 00979-1 that had an average of 2.36 and 2.26 mg/L, respectively. The amount of nitrogen fixed from all the varieties ranged from 73.547 to 154.254 kg.ha-1 . The grain yield among the genotypes ranged from 89.24 to 785.29 kg.ha-1 . The top yielding varieties were ICEAP 01159 and ICEAP 00557 with grain yields of 785.29 and 661.51 kg.ha-1 . ICEAP 01159 and ICEAP 00557 are the varieties that produced the highest grain yields and they are recommended for cultivation and breeding purposes. / NRF (National Research Foundation)

[pt] A noradrenalina desempenha um papel central em diversos transtornos relacionados ao medo, como o transtorno de ansiedade generalizada (TAG). Estudos farmacológicos em humanos e animais mostraram que os comportamentos relacionados ao medo podem ser regulados pela aplicação sistêmica de drogas noradrenérgicas. No entanto, as diferenças individuais na ansiedade-traço são frequentemente negligenciadas ao estudar os efeitos não apenas de drogas noradrenérgicas, mas de outros compostos. No presente estudo, examinamos os efeitos da ioimbina, um antagonista do receptor alfa2-adrenérgico, em duas linhagens de ratos criados para respostas de alto e baixo congelamento à pistas contextuais previamente associadas a choques nos pés (ratos Carioca de Alto e Baixo Congelamento - CAC e CBC, respectivamente). Descobrimos que a administração sistêmica de ioimbina no segundo dia de condicionamento do medo contextual (sessão de teste) diminuiu significativamente as respostas de congelamento de fêmeas CAC, mas não de machos. No entanto, o tratamento com ioimbina induziu um aumento significativo no comportamento de congelamento de ratos CBC machos e fêmeas. Resultados semelhantes foram observados quando os grupos foram novamente expostos à mesma câmara de condicionamento 6 dias depois. Nossos resultados indicam que, embora a ioimbina leve a efeitos ansiolíticos em ratos CAC, ela tem um efeito ansiogênico nos ratos CBC. Entretanto, esse efeito foi mais evidente nas fêmeas do que nos machos. Nossas descobertas apontam para o papel da noradrenalina na regulação e mediação das respostas de medo em diferentes traços de ansiedade. Além disso, nossos resultados também ressaltam a relevância do uso de ambos os sexos em estudos comportamentais e farmacológicos usando modelos animais de transtornos de ansiedade. / [en] Norepinephrine plays a central role in several fear-related disorders, such as generalized anxiety disorder (GAD). Pharmacological studies in humans and animals have shown that fear-related behaviors can be regulated by the systemic application of noradrenergic drugs. However, individual differences in trait anxiety are often overlooked when studying the effects of not only noradrenergic drugs, but other compounds. In the present study we examined the effects of yohimbine, an alpha2-adrenergic receptor antagonist, in two lines of rats bred for high and low freezing responses to contextual cues previously associated with footshocks (Carioca high- and low-conditioned freezing rats - CHF and CLF, respectively). We found that systemic administration of yohimbine on the second day of contextual fear conditioning (test session) significantly decreased the freezing responses of CHF females, but not CHF males. Yet, yohimbine treatment induced a significant increase in freezing behavior of both male and female CLF rats. Similar results were observed when groups were re-exposed to the same conditioning chamber 6 days later. Our findings indicate that while yohimbine leads to anxiolytic effects on CHF rats, it has an anxiogenic effect on CLF ones. However, such effect was more evident in females than in males. Our findings point to the role of norepinephrine in regulating and mediating fear responses in different anxiety traits. Furthermore, our findings also underscore the relevance of using both sexes in behavioral and pharmacological studies using animal models of anxiety disorders.