收获期和收割留茬高度对高羊茅种子产量和质量的影响

于2016年在上海交通大学闵行校区高羊茅(Festuca arundinacea)种子生产田实施了4个收获期和2个收割高度的两因素随机完全区组试验,以研究收获期和收割留茬高度对种子产量和质量的影响。试验结果表明:收获期从花后15 d至花后36 d,有籽粒脱落的穗子和有籽粒脱落的小穗的百分率和千粒重逐渐提高,而每小穗粒数逐渐下降,致使种子产量先增加后降低;在4个收获期处理中,最高籽粒产量出现在第2期,即花后22 d,其显著高于第1期(花后15 d)和第4期(花后36 d)的种子产量,而与第3期(花后29 d)收获的种子产量间没有显著差异;第2期收获的种子千粒重、种子发芽率和种子萌发苗株高与第3、4期收获的优质种子间没有显著差异;籽粒产量和质量在留茬高度16 cm(收割全株)和留茬高度58 cm(割穗)间差异不显著,该效应不随收获期的不同而异。据此推断:上海地区高产优质高羊茅种子的适宜收获期为首批开花穗的花后22～29 d,于全田尚有12%的嫩穗和59%的小穗顶部有1～3粒籽粒脱落时开始尽快收获;可以根据不同收获方式的需要在高于地面16 cm至穗颈节间(割穗留茬高度)范围内灵活确定植株收割高度。

Effects of harvesting time and swathing stubble height on seed yield and quality in tall fescue

In order to study the response of seed yield and quality to seed harvesting time and swathing stubble height,a two-factor randomized complete block experiment with four harvest dates and two swathing heights was conducted in the seed production field of tall fescue(Festuca arundinacea) in Minhang campus of Shanghai Jiaotong University in 2016.Results from this research showed that,while the percentages of seedheadand spikelet with shattered grains and 1000-grain weight were getting higher,the number of grains per spikelet was getting lower,which resulted in the increase first and then decrease of the seed yield,as harvesting date prolonged from 15 to 36 d after anthesis.Of the four harvesting-date treatments,seed yield was the highest for the 2nd harvesting treatment,22 d after anthesis,which was significantly higher than those harvested for the 1st(22 d after anthesis) and 4th(36 d after anthesis) harvest time treatment,and similar to those for the 3rd,29 d after anthesis,harvesting treatment.However,1000-seed weight,seed germination rate and seedling height of the 2nd harvesting time were not significantly lower than those of high quality seeds harvested for the 3rd and 4th time.Moreover,no significant difference of seed yield and seed quality was observed between two treatments of swathing stubble height,stubble height 16 cm(swathing whole plant) and stubble height 58 cm(swathing seedhead),which did not vary with the harvesting times.Theresults suggested that,for the sake of high-yield and high-quality seeds of tall fescue in Shanghai,the appropriate seed harvesting time was between 22 and 29 d after anthesis,beginning when about 12% of the seedheads are immature and 59% of spikelet with 1-3 grains shattered and finishing the harvest as soon as possible within one week;the swathing stubble height could be determined flexibly from 16 cm above the ground to neck-panicle node(stubble height for swathing seedhead)according to the requirements of different harvesting methods.