KERAGAAN PROGENI F1 TANAMAN KARET HASIL PERSILANGAN 2011-2012 DI SEEDLING EVALUATION TRIAL

Salah satu upaya untuk menghasilkan klon karet unggul baru adalah melalui persilangan buatan antar klon tetua yang memiliki karakter spesifik dan hubungan kekerabatan genetik yang jauh. Berdasarkan Standart Operatioal Procedure (SOP) seleksi progeny F1 hasil persilangan terdiri dari beberapa tahap yaitu seleksi progeni F1 di Seedling Evaluation Trial (SET), uji pendahulan (Small Scale Clone Trial (SSCT), uji lanjutan (Large Scale Clone Trial/LSCT) dan uji multilokasi (adaptation trial). Pada penelitian ini dilaporkan hasil seleksi 215 progeni F1 hasil persilangan tiga kombinasi klon tetua yaitu BPM 24 x PB 260, IRR 104 X PB 260 dan PB 260 X TJIR 1 dengan klon pembanding AVROS 2037. Pengamatan dilakukan terhadap lilit batang, tebal kulit, jumlah pembuluh lateks, panjang alur sadap, produksi normal dengan sistem sadap S/2d3 dan aplikasi ethrel 2,5% setiap bulan, serta ketahanan progeny terhadap penyakit gugur daun utama. Hasil penelitian menunjukkan bahwa terdapat korelasi antara parameter produksi dengan lilit batang, tebal kulit, jumlah pembuluh lateks dan panjang alur sadap. Berdasarkan seleksi 1% parameter produksi lateks, terpilih tujuh progeny yaitu HP2011/215, HP2011/54, HP2011/170, HP2011/200, HP2011/213. HP2011/158 dan HP2011/18. Progeni tersebut selanjutnya akan diuji ke tahap SSCT.

How aging affects visuomotor adaptation and retention in a precision walking paradigm

Motor learning is a lifelong process. However, age-related changes to musculoskeletal and sensory systems alter the relationship (or mapping) between sensory input and motor output, and thus potentially affect motor learning. Here we asked whether age affects the ability to adapt to and retain a novel visuomotor mapping learned during overground walking. We divided participants into one of three groups (n = 12 each) based on chronological age: a younger-aged group (20–39 years old); a middle-aged group (40–59 years old); and an older-aged group (60–80 years old). Participants learned a new visuomotor mapping, induced by prism lenses, during a precision walking task. We assessed retention one-week later. We did not detect significant effects of age on measures of adaptation or savings (defined as faster relearning). However, we found that older adults demonstrated reduced initial recall of the mapping, reflected by greater foot-placement error during the first adaptation trial one-week later. Additionally, we found that increased age significantly associated with reduced initial recall. Overall, our results suggest that aging does not impair adaptation and that older adults can demonstrate visuomotor savings. However, older adults require some initial context during relearning to recall the appropriate mapping.

Nationally Released Tef Variety Adaptation Trial in North Western Tigray, North Ethiopia, 2018

Nowadays tef is becoming the most preferred crop both for consumption and market value. However, its production and productivity is still very low due to traditional agronomic practices, nutrient deficiencies, and lack of improved varities and susceptibility of the crop to lodging. So, the current trial was carried out during 2017 and 2018 cropping seasons in Medebay zana district at onstation with twenty eight nationally released tef varieties including standard and local check were evaluated with the objective of selecting adaptable and best performing tef variety/ies. Alpha lattice experimental design with three replications was used on plot size of 2mx2m [1]. The data recorded were days to 50% heading and 75% physiological maturity plant height, panicle length, grain yield, biomass yield and harvest index. The data was analyzed using Genestat software and means were separated using Duncan mulple range test (DMRT). The combined two years data analysis showed that varieties varied significantly for most studied traits at (P<0.01 and (P<0.05). Based on the obtained result, two improved tef varieties namely; Niguse shown to be high yielder variety followed by the varieties Tesfa and Guduru with the values of 1880.0, 1769.0 and 1692.0 kg ha-1, respectively, greater than 20% yield increment than local variety . The varieties Guduru, Wollenkomi and Magna were found to be having high biomass with the values of 9599.0, 9166.0 and 9139.0 kg ha-1, respectively. So, Niguse was superior in almost all the agronomic traits evaluated while the local variety of Abat tef and was out performed by most of the improved varieties of teff tested. Therefore, based on objectively measured traits, the variety Niguse was found most promising having the potential to increase the average yield of tef in Medebay zana district and is therefore recommended for general cultivation through demonstration and pre extension popularization activity as alternative tef variety for production at the testing and similar sites.