Field performance of anther culture-derived breeding lines of barley

Non-Peer ReviewedSince 1984, evaluation of anther culture derived lines has been carried out at the University of Saskatchewan. The anther culture method has been compared to pedigree, single seed descent, and Hordeum bulboeum methoda of cultivar production. In 1986 and 1987, the lines were evaluated in yield trials with grain yield, heading date, thousand kernel weight, hectolitre weight, kernels per spike, and percentage plump kernels were examined. In assessment of the cross of Abee and Norbert the means of the analyzed traits were found to be generally lower for anther culture, but variability was similar among all methods. Furthermore, the best lines of each method expressed similar potential. In the current studies the performance of the Abee/Norbert cross appears to support the previous evidence of lower mean performance. Materials from the crosses of Abee/Harrington and Abee/TR215 were also grown in 1987 for assessment

A simpler and more efficient algorithm for the next-to-shortest path problem

Given an undirected graph $G=(V,E)$ with positive edge lengths and two vertices $s$ and $t$, the next-to-shortest path problem is to find an $st$-path which length is minimum amongst all $st$-paths strictly longer than the shortest path length. In this paper we show that the problem can be solved in linear time if the distances from $s$ and $t$ to all other vertices are given. Particularly our new algorithm runs in $O(|V|\log |V|+|E|)$ time for general graphs, which improves the previous result of $O(|V|^2)$ time for sparse graphs, and takes only linear time for unweighted graphs, planar graphs, and graphs with positive integer edge lengths.Comment: Partial result appeared in COCOA201

Canadians Should Travel Randomly

We study online algorithms for the Canadian Traveller Problem (CTP) introduced by Papadimitriou and Yannakakis in 1991. In this problem, a traveller knows the entire road network in advance, and wishes to travel as quickly as possible from a source vertex s to a destination vertex t, but discovers online that some roads are blocked (e.g., by snow) once reaching them. It is PSPACE-complete to achieve a bounded competitive ratio for this problem. Furthermore, if at most k roads can be blocked, then the optimal competitive ratio for a deterministic online algorithm is 2k + 1, while the only randomized result known is a lower bound of k + 1. In this paper, we show for the first time that a polynomial time randomized algorithm can beat the best deterministic algorithms, surpassing the 2k + 1 lower bound by an o(1) factor. Moreover, we prove the randomized algorithm achieving a competitive ratio of (1 + [√2 over 2])k + 1 in pseudo-polynomial time. The proposed techniques can also be applied to implicitly represent multiple near-shortest s-t paths.NSC Grant 102-2221-E-007-075-MY3Japan Society for the Promotion of Science (KAKENHI 23240002