The time to develop new cultivars and introduce them into cultivation is an issue of major importance in plant breeding. This is because plant breeders have an urgent need to help provide solutions to feed a growing world population, while in parallel, time savings are linked to profitability. Plant breeding processes may in general be broken down into the following five key elements: (1) germplasm variation; (2) crossing; (3) generation of new genetic combinations; (4) screening and selection (identification and subsequent fixation of desired allelic combinations); and (5) line/cultivar development. Each of these has implications in relation to the time taken to breed a new cultivar; a brief introduction is given for each to highlight the obstacles that may be targeted in accelerating the breeding process. Specific techniques that provide a time advantage for these elements are then discussed. Some targets for enhancing the efficiency of plant breeding, e.g., the manipulation of meiotic recombination, have proven to be recalcitrant. However, other methods that create new genetic variation along with improvements in selection efficiency compensate to a large extent for this limitation. Progress in accelerating the plant breeding process continues by exploiting new emerging ideas in science and technology.

Stay-green trait enhances sorghum adaptation to post-flowering drought. Six stay-green backcross introgression lines (BILs) carrying one or more stay-green QTLs (Stg1-4) and their parents were characterized under non-stress (W100: 100% of soil field capacity (FC)) and two levels of post-flowering drought (W75: 75% FC; W50: 50% FC) in a controlled condition. We aimed to study the response and identify the drought threshold of these QTLs under different levels of post-flowering drought and find traits closely contributing to grain yield (GY) under different drought severity. W50 caused the highest reduction in BILs performance. From W100 to W50, the GY of the recurrent parent reduced by 70%, whereas that of the BILs reduced by only 36%. W75 and W50 induce different behavior/response compared to W100. Harvest index contributed to the GY under the three water regimes. For high GY under drought transpiration rate at the beginning of drought and mid-grain filling was important at W75, whereas it was important at mid-grain filling and late-grain filling at W50. Stay-green trait can be scored simply with the relative number of green leaves/plants under both irrigated and stress environments. QTL pyramiding might not always be necessary to stabilize or increase the GY under post-flowering drought. The stay-green QTLs increase GY under drought by manipulating water utilization depending on drought severity.

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