Er~vironmrr~t,al a.rrd cultr~ritl fkr.tors that In:&! li~nit tlrr yield of' short-tiurnti011 pigronpt>tt wrrcb ir~vrstigat.rd ovcbr t h rrr .sfxttsons. I'li~nts irr t htt [)c~~xir~sr~li~r Indiarr cinrironrnrnt a t l ' a t a r~( . h t r~ grew Irss and prociuced less dry niattrr try tirst -tlt~slr r r~i~t r~r i t y than at. Hiaar, a loc.atioti in northrrri Indiit whew t h r c~nvirorrnic.nt is caonsiclrrt.tl fhvourahlr for the, growth of short-durittion pigeonpca. Howevc.r. with a sirr~ilar sou ir~g date in ,luncs, the Inran seed yitalds of three g c~~o t y j ) e s .I{'I'T, 4. It'I'I, X I anti I('l'l, 8 7 , wtzr,r very similar, at about 2.3 t/ha. irr t~ot,h c.nviror~rrrrnts. This was nrairrly tlrlt. to tht, hig1rt.r ratio of' grain to ttt)ov~-grolirrd dry nliittjt2r a t Patnr~csheru. Trr i~clclitiorl to thtb tirst hilrvr.st. all gellotypes S~O W ( A~ a ptrt,ential for two more hnrvests owing t>o t h r warm uirrtrrs at P:tt.ctncht.ru. The potc.nt,ial for multiplr httrvctsts wits particaularly high irr I('1'1, X i . wlrit.li yirldrd 5.2 t / h a from three harvtlsts in 1!182-3. 3.6 t / h i~ from two har\~rsts in I!)X:3 4 . iii~ti 4.1 t / h a fiorn thncv, Irtirvrsts i l l I!4H4 5. 'l'htx optirr~uni plant l~oflulittior> drrrs~ty at I'atar~c.hrri~ was "-35 ~)Iants/rn' for TC'l'I, 87. t~u t was higher for t h r othtbr t u c~ genotypes.At Pat,arichr~ru. t.he totitl dry-rrictt,trr and sred yic,ld of' first and sut)sc.cl~~rnf h;irvc*sts wrre signiticit~rtly retlucat.ti by deliving sowing b e o n d ,Jurir. (:er~rrally. t11c. st.c~on(i-i~r~d the third-triirvest vieltfs u-ere, Iowrr 011 \-r)rtisol than on ;tlfisol untlrr t)otlr irrivaird ant1 urrirrigatrd t:orrditions. l'he total yield ofTC'1'1, 87 fi.o~n two harvr5t.s was f'ar higher than thirt of'a well-atiitptt~cl r~retiiurn-dur,ittio~r gt3riotyf)e B U S 1, grown over it sirnilar 1)rriod. I'hr yirld irtlvant,agv M its grrnt,er on the alfisol 1)erause of'the t)et,t,er nrult,iplr harvest pct,c,ntial of' this soil. Thr result,s of this study dc~monst,rat~t. that propc.rly rrra~lagc.d short-ciuration grrlotyj)c s of pigronpeit may have c~onsidrrahle potrrrtial for inc.rrased yield f'ronr multiplr hiirvc.sts in environnrrnts wht~rr winters art. warm t~rrough t o 1)rrlnit r o n t i r~~i r d growt>h.with the followiny; ohlect~ves ( a ) to drtermlne t h~

Second harvest yields of medium duration pigeonpeas (Cajanus cajan) in peninsu!ar India. Field Crops Res., 10 : 323-332. In Peninsular India medium duration pigeonpeas (Cajanus cajan) are normally sown soon after the onset of the monsoon, in June or July; they mature around December, when they are usually cut down and removed from the field. However, if they are harvested by ratooning or by picking the pods, the plants go on to produce a second flush of pods, which matures around March. In experiments conducted in four growing seasons at ICRISAT Center, second harvest yields were usually greater for non-ratooned than ratooned plants, and in experiments conducted on Vertisols they were greater for the plants ratooned high up in the plant than for those cut closer t o the ground. Second harvest yields of non-ratooned plants without irrigation o n Alfisols were on average 66% of the first harvest yields, but on Vertisols only 37%, in spite of the greater water-holding capacity of the latter. On Alfisols second harvest yields were approximately doubled by a single irrigation, but there was less response t o irrigation o n Vertisols. The poorer second harvest yields on Vertisols may have been due t o the damaging effects of soil cracking o n the root system of the plants. In non-ratooned plants from which the first and second flushes of pods were harvested together, yields were less than the total yield obtained from non-ratooned plants in two harvests, even though the yield loss, mainly due to pod shattering, was as little as 4% in one year. The taking of second harvests from pigeonpeas grown o n Alfisols may have considerable potential as a method of obtaining additional yield for little extra cost.

S U M M A R YIn field experiments carried out at Hyderabad, India with early and mediumduration cultivars of Cujunus cajan sown at the normal time, in July, removal of all flowers and young pods for up to 5 wk had little or no effect on final yield. The flowering period of the deflowered plants was extended and their senescence delayed. The plants compensated for the loss of earlier-formed flowers by setting pods from later-formed flowers; there was relatively little effect of the deflowering treatments on the number of seeds per pod or weight per seed. The plants were also able to compensate for the repeated removal of all flowers and young pods from alternate nodes by setting more pods at the other nodes.The removal of flowers from pigeonpeas grown as a winter crop resulted in yield reductions roughly proportional to the length of the deflowering period, probably because maturation of these plants was delayed and occurred under increasingly unfavourable conditions as the weather became hotter.

Short-duration pigeonpea can give up to three harvests in environments with mild winters (e.g. minimum temperature above 10 °C) such as those prevailing in peninsular India (Sharma, Saxena & Green. 1978; Chauhan, Venkataratnam & Sheldrake, 1984). This is mainly due to the short time (about 120 days) taken to produce the first flush, and the strong perennial character of pigeonpea. The seed yield of short-duration pigeonpea in this multipleharvest system may reach 5'2 t/ha (Chauhan et al. 1984). Venkataratnam & Sheldrake (1985) found that the yield of the second harvest of medium-duration pigeonpea was significantly influenced by the method of harvesting of the first flush. The lower the plants were cut, the smaller were the second-harvest yields. A positive relationship between the height at which the stem was cut and success of ratooning was also reported by Suarez & Herreara (1971). Tayo (1985), however, found that in the lowland tropics, plants of a dwarf pigeonpea variety ratooned at 0-3 m had better growth and yield than hand-picked plants; ratooning at 0-6 m height was intermediate. Information on the effect of different harvest methods on yield of short-duration pigeonpea in subtropical, semi-arid environments is not available. The objective of this study was to obtain this information.On both soils two short-duration pigeonpea genotypes, ICPL 81 (indeterminate) and ICPL 87 (determinate), were sown on 15 June 1984 on both sides of 0-6 m ridges at a spacing of 03 x0-1 m. At first-flush maturity the following three harvest methods were applied to the crop which had grown about 1 m tall:(1) cutting off the shoots 0 -6 m above ground level (ratooning), (2) hand picking the mature pods on the plant, and (3) no harvest (single-harvest only at the second-flush maturity). The experimental treatments of harvest methods and genotypes were laid out in a randomized-block design. There were four replications on each soil and the plot size was 6 x 4 m. On both soils, about 19 in 2 per plot was harvested for yield estimation. The experiment on the alfisol was irrigated 10 and 20 weeks after sowing (WAS) and that on the vertisol at 11 and 21 WAS. Labour records were kept during the first harvest. In all the treatments, at the second-flush maturity, all pods of plants were harvested by cutting the stems at ground level. All harvested material was threshed by machine and the seed was sun-dried to a moisture content of 8-9% before weighing. The pods that dropped off, mainly during the second flush and its harvest, were also carefully collected and threshed, and their seed yield was included in the second-flush yield of the ratooning and hand picking treatment, and in the total yield of the single-harvest treatment. MATERIALS AND METHODSThe experiments were conducted on an alfisol (Udic Rhodustalf) and a vertisol (Typic Pellustert) at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) Centre (17 °N, 78 °.E, 545 m elevation) in 1984-5. The alfisols generally hold less than 100 mm plant-available w...